Merge origin/master (generic task runtime #219, single-exe closure, package renames)

Semantic resolutions beyond line merges:
- The bash seam keeps resolveMode + the bash/resolve-mode waterfall on
  master's task-free BashExecutor (run/start/resolve only; BashProcess
  handles); tool-bash consults it at its stamping site and escalation
  baseline on master's render/background split, with a waterfall test on
  the recording executor.
- dsh-mode's BASH_FAMILY narrows to ['bash']: bash_output/bash_kill are
  replaced by the kind-generic task_output/task_kill, which span every
  task kind and only observe or stop work, so the access cap withholds
  only the starter it can reason about.
- The plan-mode snapshot suite adopts master's pin grammar (tool-schema
  sidecars; the expectedHeaderSnapshots extension is gone — the exit
  transition deltas, and entering-before-turn-1 needs no second
  snapshot); modes-advertise joins the plan header class (no-model, so
  membership is vacuous). Fixtures re-recorded on the acp-demo bin;
  the replay overlay gains the passthrough sandbox runner.
- examples/plan-acp-agent rewires to @deepseek-ai/dsh-acp-demo and drops
  its tool-bash entry (the spine bundle now composes it); dsh-stdio (the
  renamed stdio-chat home) keeps its /mode command and gains the dsh-mode
  peer edge; the acp bridge keeps the modes surface beside master's
  permission presets.
- mode README gains the Model Experience / Known Limitations sections the
  new README gates require; AGENTS.md ceiling 1370 → 1440 for the kept
  mode/ layout line and Agent efficiency section.

docs/capability-seams.md

@@ -18,12 +18,14 @@ flowchart LR
   svc_sessions["ctx.sessions<br/>In-memory session store"]
   pkg_agent["agent"]
   pkg_session_persistence["session-persistence"]
+  pkg_session_query["session-query"]
   pkg_subagent_inprocess["subagent-inprocess"]
   pkg_invariants["invariants"]
   svc_sessionPersistence["ctx.sessionPersistence<br/>Durable session persistence seam"]
   pkg_session_persistence_jsonl["session-persistence-jsonl"]
   pkg_session_persistence_sqlite["session-persistence-sqlite"]
   pkg_acp["acp"]
+  svc_sessionQuery["ctx.sessionQuery<br/>Exact session-history reads"]
   pkg_system_prompt["system-prompt"]
   svc_systemPrompt["ctx.systemPrompt<br/>System prompt assembly registry"]
   pkg_tools["tools"]
@@ -38,15 +40,16 @@ flowchart LR
   pkg_tool_todo["tool-todo"]
   pkg_user_interaction["user-interaction"]
   svc_userInteraction["ctx.userInteraction<br/>Human question/answer seam"]
-  pkg_stdio_agent["stdio-agent"]
+  pkg_stdio_demo["stdio-demo"]
   pkg_mode["mode"]
   svc_modes["ctx.modes<br/>Session-mode policy state"]
+  pkg_stdio_agent["stdio-agent"]
   pkg_skill["skill"]
   svc_skills["ctx.skills<br/>Skill provider registry"]
   pkg_skill_local["skill-local"]
   svc_agents["ctx.agents<br/>Agent registry"]
   svc_agentLoop["ctx.agentLoop<br/>Concrete loop driver"]
-  pkg_agent_core["agent-core"]
+  pkg_agent_spine_demo["agent-spine-demo"]
   pkg_bash["bash"]
   svc_bash["ctx.bash<br/>Bash executor seam"]
   pkg_bash_local["bash-local"]
@@ -58,6 +61,8 @@ flowchart LR
   pkg_sandbox_local["sandbox-local"]
   pkg_approval["approval"]
   svc_approval["ctx.approval<br/>Approval seam"]
+  pkg_permission["permission"]
+  svc_permission["ctx.permission<br/>Permission presets"]
   pkg_code_runtime["code-runtime"]
   svc_codeRuntime["ctx.codeRuntime<br/>Code-execution seam"]
   pkg_code_runtime_worker["code-runtime-worker"]
@@ -73,6 +78,9 @@ flowchart LR
   pkg_subagent_fork["subagent-fork"]
   pkg_subagent_acp["subagent-acp"]
   pkg_subagent_mock["subagent-mock"]
+  pkg_tasks["tasks"]
+  svc_tasks["ctx.tasks<br/>Background task registry"]
+  pkg_tool_tasks["tool-tasks"]
   pkg_web["web"]
   svc_web["ctx.web<br/>Web access provider registry"]
   pkg_web_search_exa["web-search-exa"]
@@ -102,21 +110,24 @@ flowchart LR
   pkg_llm_pi_ai --> svc_llm
   pkg_llm_replay --> svc_llm
   pkg_mode --> svc_modes
+  pkg_permission --> svc_permission
   pkg_sandbox --> svc_sandbox
   pkg_sandbox_local --> svc_sandbox
   pkg_session --> svc_sessions
   pkg_session_persistence --> svc_sessionPersistence
   pkg_session_persistence_jsonl --> svc_sessionPersistence
   pkg_session_persistence_sqlite --> svc_sessionPersistence
+  pkg_session_query --> svc_sessionQuery
   pkg_skill --> svc_skills
   pkg_skill_local --> svc_skills
-  pkg_stdio_agent --> svc_userInteraction
+  pkg_stdio_demo --> svc_userInteraction
   pkg_subagent --> svc_subagents
   pkg_subagent_acp --> svc_subagents
   pkg_subagent_fork --> svc_subagents
   pkg_subagent_mock --> svc_subagents
   pkg_subagent_spawn --> svc_subagents
   pkg_system_prompt --> svc_systemPrompt
+  pkg_tasks --> svc_tasks
   pkg_tools --> svc_tools
   pkg_user_interaction --> svc_userInteraction
   pkg_web --> svc_web
@@ -126,11 +137,11 @@ flowchart LR
   pkg_web_search_perplexity --> svc_web
   pkg_workflow --> svc_workflows
   pkg_workflow_workerthread --> svc_workflows
-  svc_agentLoop --> pkg_agent_core
+  svc_agentLoop --> pkg_agent_spine_demo
   svc_agents --> pkg_acp
   svc_agents --> pkg_agent_loop
   svc_agents --> pkg_invariants
-  svc_agents --> pkg_stdio_agent
+  svc_agents --> pkg_stdio_demo
   svc_agents --> pkg_subagent_inprocess
   svc_approval --> pkg_tool_bash
   svc_approval --> pkg_tools
@@ -144,13 +155,16 @@ flowchart LR
   svc_llm --> pkg_compact_basic
   svc_modes --> pkg_acp
   svc_modes --> pkg_stdio_agent
+  svc_permission --> pkg_acp
   svc_sandbox --> pkg_bash_sandbox
   svc_sessionPersistence --> pkg_acp
   svc_sessionPersistence --> pkg_agent_loop
+  svc_sessionPersistence --> pkg_session_query
   svc_sessions --> pkg_agent
   svc_sessions --> pkg_agent_loop
   svc_sessions --> pkg_invariants
   svc_sessions --> pkg_session_persistence
+  svc_sessions --> pkg_session_query
   svc_sessions --> pkg_subagent_inprocess
   svc_skills --> pkg_tool_skill
   svc_subagents --> pkg_tool_subagent
@@ -158,6 +172,9 @@ flowchart LR
   svc_systemPrompt --> pkg_tool_fs
   svc_systemPrompt --> pkg_tool_web
   svc_systemPrompt --> pkg_tools
+  svc_tasks --> pkg_tool_bash
+  svc_tasks --> pkg_tool_subagent
+  svc_tasks --> pkg_tool_tasks
   svc_tools --> pkg_acp
   svc_tools --> pkg_agent_loop
   svc_tools --> pkg_tool_ask_user
@@ -169,7 +186,7 @@ flowchart LR
   svc_tools --> pkg_tool_todo
   svc_tools --> pkg_tool_web
   svc_userInteraction --> pkg_acp
-  svc_userInteraction --> pkg_stdio_agent
+  svc_userInteraction --> pkg_stdio_demo
   svc_userInteraction --> pkg_tool_ask_user
   svc_web --> pkg_tool_web
   svc_workflows --> pkg_tool_workflow
@@ -179,22 +196,25 @@ flowchart LR
 | ctx key | Role | Owner | Implementations | Direct consumers | Companion plugins | Note |
 | --- | --- | --- | --- | --- | --- | --- |
 | `ctx.llm` | `seam` | [`llm`](../packages/llm/llm) | [`llm-deepseek`](../packages/llm/llm-deepseek), [`llm-pi-ai`](../packages/llm/llm-pi-ai), [`llm-replay`](../packages/support/llm-replay) | [`agent-loop`](../packages/core/agent-loop), [`compact-basic`](../packages/compact/compact-basic) | - | Adapters register provider implementations; the loop and compaction call the provider-neutral stream service. |
-| `ctx.sessions` | `core` | [`session`](../packages/core/session) | - | [`agent-loop`](../packages/core/agent-loop), [`agent`](../packages/core/agent), [`session-persistence`](../packages/session-persistence/session-persistence), [`subagent-inprocess`](../packages/subagent/subagent-inprocess), [`invariants`](../packages/support/invariants) | - | Owns append-only Session instances and emits the durable session event feed. |
-| `ctx.sessionPersistence` | `seam` | [`session-persistence`](../packages/session-persistence/session-persistence) | [`session-persistence-jsonl`](../packages/session-persistence/session-persistence-jsonl), [`session-persistence-sqlite`](../packages/session-persistence/session-persistence-sqlite) | [`agent-loop`](../packages/core/agent-loop), [`acp`](../packages/ui/acp) | - | Backends persist the same SessionEvent vocabulary; apps choose a backend at composition time. |
+| `ctx.sessions` | `core` | [`session`](../packages/core/session) | - | [`agent-loop`](../packages/core/agent-loop), [`agent`](../packages/core/agent), [`session-persistence`](../packages/session-persistence/session-persistence), [`session-query`](../packages/session-query/session-query), [`subagent-inprocess`](../packages/subagent/subagent-inprocess), [`invariants`](../packages/support/invariants) | - | Owns append-only Session instances and emits the durable session event feed. |
+| `ctx.sessionPersistence` | `seam` | [`session-persistence`](../packages/session-persistence/session-persistence) | [`session-persistence-jsonl`](../packages/session-persistence/session-persistence-jsonl), [`session-persistence-sqlite`](../packages/session-persistence/session-persistence-sqlite) | [`agent-loop`](../packages/core/agent-loop), [`acp`](../packages/ui/acp), [`session-query`](../packages/session-query/session-query) | - | Backends persist the same SessionEvent vocabulary; apps choose a backend at composition time. |
+| `ctx.sessionQuery` | `seam` | [`session-query`](../packages/session-query/session-query) | - | - | - | Resolves live and optional persisted logs into one logical corpus for exact reads. |
 | `ctx.systemPrompt` | `core` | [`system-prompt`](../packages/core/system-prompt) | - | [`agent-loop`](../packages/core/agent-loop), [`tools`](../packages/core/tools), [`tool-fs`](../packages/fs/tool-fs), [`tool-web`](../packages/web/tool-web) | - | Collects prompt sections and model-facing tool schemas for each step. |
 | `ctx.tools` | `core` | [`tools`](../packages/core/tools) | - | [`agent-loop`](../packages/core/agent-loop), [`tool-ask-user`](../packages/ui/tool-ask-user), [`tool-bash`](../packages/bash/tool-bash), [`tool-cordis`](../packages/cordis/tool-cordis), [`tool-fs`](../packages/fs/tool-fs), [`tool-skill`](../packages/skill/tool-skill), [`tool-subagent`](../packages/subagent/tool-subagent), [`tool-todo`](../packages/todo/tool-todo), [`tool-web`](../packages/web/tool-web), [`acp`](../packages/ui/acp) | - | Registers capabilities, owns Code Mode transport, and routes calls through pre-policy, monotonic guards, around dispatch, post-policy, and final-result observation. |
-| `ctx.userInteraction` | `seam` | [`user-interaction`](../packages/ui/user-interaction) | [`stdio-agent`](../packages/ui/stdio-agent), [`acp`](../packages/ui/acp) | [`tool-ask-user`](../packages/ui/tool-ask-user), [`stdio-agent`](../packages/ui/stdio-agent), [`acp`](../packages/ui/acp) | - | UI front doors provide the active human-answer provider; tool-ask-user pauses a tool call on the provider-neutral ask() promise. |
-| `ctx.modes` | `core` | [`mode`](../packages/mode/mode) | - | [`stdio-agent`](../packages/ui/stdio-agent), [`acp`](../packages/ui/acp) | - | Folds the logged per-agent mode (mode/set), flushes user flips at turn boundaries, and enforces the mode through the assemble filter and the tools/pre-execute gate. |
+| `ctx.userInteraction` | `seam` | [`user-interaction`](../packages/ui/user-interaction) | [`stdio-demo`](../packages/examples/stdio-demo), [`acp`](../packages/ui/acp) | [`tool-ask-user`](../packages/ui/tool-ask-user), [`stdio-demo`](../packages/examples/stdio-demo), [`acp`](../packages/ui/acp) | - | UI front doors provide the active human-answer provider; tool-ask-user pauses a tool call on the provider-neutral ask() promise. |
+| `ctx.modes` | `core` | [`mode`](../packages/mode/mode) | - | `stdio-agent`, [`acp`](../packages/ui/acp) | - | Folds the logged per-agent mode (mode/set), flushes user flips at turn boundaries, and enforces the mode through the assemble filter and the tools/pre-execute gate. |
 | `ctx.skills` | `seam` | [`skill`](../packages/skill/skill) | [`skill-local`](../packages/skill/skill-local) | [`tool-skill`](../packages/skill/tool-skill) | - | Merges provider skill catalogs; tool-skill renders the session-prefix catalog and loads complete skill bodies. |
-| `ctx.agents` | `core` | [`agent`](../packages/core/agent) | - | [`agent-loop`](../packages/core/agent-loop), [`acp`](../packages/ui/acp), [`subagent-inprocess`](../packages/subagent/subagent-inprocess), [`stdio-agent`](../packages/ui/stdio-agent), [`invariants`](../packages/support/invariants) | - | Owns live Agent handles and the create/resume factory seam. |
-| `ctx.agentLoop` | `bundle` | [`agent-loop`](../packages/core/agent-loop) | - | [`agent-core`](../packages/core/agent-core) | - | The one concrete loop plugin; extension packages depend on dsh-agent events and services, not on this package. |
+| `ctx.agents` | `core` | [`agent`](../packages/core/agent) | - | [`agent-loop`](../packages/core/agent-loop), [`acp`](../packages/ui/acp), [`subagent-inprocess`](../packages/subagent/subagent-inprocess), [`stdio-demo`](../packages/examples/stdio-demo), [`invariants`](../packages/support/invariants) | - | Owns live Agent handles and the create/resume factory seam. |
+| `ctx.agentLoop` | `bundle` | [`agent-loop`](../packages/core/agent-loop) | - | [`agent-spine-demo`](../packages/examples/agent-spine-demo) | - | The one concrete loop plugin; extension packages depend on dsh-agent events and services, not on this package. |
 | `ctx.bash` | `seam` | [`bash`](../packages/bash/bash) | [`bash-local`](../packages/bash/bash-local), [`bash-sandbox`](../packages/bash/bash-sandbox) | [`tool-bash`](../packages/bash/tool-bash), [`hooks-claude`](../packages/hooks/hooks-claude), [`hooks-codex`](../packages/hooks/hooks-codex) | - | The model-facing bash tools and hook bridges consume this seam; sandboxed or remote executors replace bash-local without touching them. |
 | `ctx.sandbox` | `seam` | [`sandbox`](../packages/sandbox/sandbox) | [`sandbox-local`](../packages/sandbox/sandbox-local) | [`bash-sandbox`](../packages/bash/bash-sandbox) | - | Consumers hand over the exact argv they are about to spawn; same-world backends wrap it under a per-call policy and report enforcement. |
 | `ctx.approval` | `seam` | `approval` | [`acp`](../packages/ui/acp) | [`tools`](../packages/core/tools), [`tool-bash`](../packages/bash/tool-bash) | - | One-shot permission decisions dispatched over the `approval/request` waterfall; answerers are listeners (the ACP bridge for its own agents), absence fails closed to `unavailable`. |
+| `ctx.permission` | `core` | [`permission`](../packages/ui/permission) | - | [`acp`](../packages/ui/acp) | - | User-facing preset table (`workspace-write`/`danger-full-access`) bundling the sandbox-mode and approval-policy knobs; a switch writes one `permission/preset` event through to both knob events. |
 | `ctx.codeRuntime` | `seam` | [`code-runtime`](../packages/code-runtime/code-runtime) | [`code-runtime-worker`](../packages/code-runtime/code-runtime-worker) | [`tools`](../packages/core/tools) | - | Runs one model-written program against host-provided async bindings; backends differ by substrate and language (the tool registry consumes it for Code Mode). |
 | `ctx.fs` | `seam` | [`fs`](../packages/fs/fs) | [`fs-local`](../packages/fs/fs-local) | [`tool-fs`](../packages/fs/tool-fs) | [`fs-policy`](../packages/fs/fs-policy) | tool-fs executes read/write/edit through ctx.fs; fs-policy contributes observed-state checks through the fs/* event gate. |
 | `ctx.compact` | `seam` | [`compact`](../packages/compact/compact) | [`compact-basic`](../packages/compact/compact-basic) | [`compact-basic`](../packages/compact/compact-basic) | - | The basic backend currently consumes the pre-step event directly; a model-facing compact tool remains deferred. |
 | `ctx.subagents` | `seam` | [`subagent`](../packages/subagent/subagent) | [`subagent-spawn`](../packages/subagent/subagent-spawn), [`subagent-fork`](../packages/subagent/subagent-fork), [`subagent-acp`](../packages/subagent/subagent-acp), [`subagent-mock`](../packages/support/subagent-mock) | [`tool-subagent`](../packages/subagent/tool-subagent) | - | Providers implement transports; tool-subagent exposes one configured provider as a model-facing tool name. |
+| `ctx.tasks` | `core` | [`tasks`](../packages/tasks/tasks) | - | [`tool-bash`](../packages/bash/tool-bash), [`tool-subagent`](../packages/subagent/tool-subagent), [`tool-tasks`](../packages/tasks/tool-tasks) | - | Producers (tool-bash background commands, tool-subagent background delegations) register running work; tool-tasks is the model-facing control surface that reads, lists, and kills it. |
 | `ctx.web` | `seam` | [`web`](../packages/web/web) | [`web-search-exa`](../packages/web/web-search-exa), [`web-search-perplexity`](../packages/web/web-search-perplexity), [`web-search-deepseek`](../packages/web/web-search-deepseek), [`web-fetch-local`](../packages/web/web-fetch-local) | [`tool-web`](../packages/web/tool-web) | - | Search and fetch providers register into one ctx.web seam; tool-web owns the stable model-facing names. |
 | `ctx.workflows` | `seam` | [`workflow`](../packages/workflow/workflow) | [`workflow-workerthread`](../packages/workflow/workflow-workerthread) | [`tool-workflow`](../packages/workflow/tool-workflow) | - | One engine per context (bash shape, no named-provider registry); the worker-thread engine fans agent() calls out through ctx.subagents. |