Merge origin/master: scope-aware fusion of the tools/execute seam, session-prefix, and tool-cordis

Master brought 50 commits (the tool-cordis group, dsh-code-runtime + worker,
the tools/execute around-dispatch seam + timeout-policy, repeat-tool-guard,
agent/session-prefix, the ui reorganization). Beyond the ten textual
conflicts, the merge reconciles master's new seams with this branch's
scoped-registration world:

- tools/execute (new waterfall around core dispatch): dispatched with the
  SAME exec.agent carrier as the pre/post waterfalls — an agent.ctx wrapper
  times/retries only its own agent's calls — and its base thunk resolves the
  tool through the caller's visible view (get(exec.name, exec.agent)), so a
  scoped/shadowed tool dispatches and a restricted-away global stays
  UNKNOWN_TOOL. Declared this: Scoped<ToolRegistry> with the scope-filtered
  doc sentence; invariants table + verify-scoped-dispatch pin it (21 events).
- agent/session-prefix (new waterfall, once per loop instance): composed via
  the fused agentEvents dispatcher (scope-filtered like every agent-subject
  event), declared this: Scoped<Agent>, table-pinned. agent/pre-step keeps
  master's new sessionPrefix parameter with this branch's Scoped this.
- timeout-policy reads the budget through the caller's visible view
  (get(exec.name, exec.agent)): a scoped tool's own timeoutMs governs its
  calls; a global name-twin's budget is never misapplied to a shadowing
  per-agent variant.
- tool-cordis: cordis_inspect's tools section lists the CALLING agent's view
  (its description promises "what you can call"); the sandbox tool façade's
  reads resolve through the mount's own scope, mirroring where its register
  lands writes; sandboxRegisterTool's return type carries the exact-disposer
  union honestly. dsh-scope declared as peer+dev with the project reference.
- doc-sync chain unions master's verify-cordis-api with this branch's
  verify-scoped-dispatch; the generated catalogs, event matrix (the
  zero-dispatcher guard passes over master's new events), module graph, and
  the cordis api-catalog are regenerated on the merged surface.

Full gate sequence green on the merged tree: typecheck, lint, per-file 100%
coverage (2668 tests), snapshots (38), doc-sync, module graph, build,
hygiene, demo smoke.

docs/cordis-catalog/services.md

@@ -98,11 +98,13 @@ Implementations MUST honor:
 - **Blocking**: no compaction begins while another is in progress for the same session. The recommended mechanism is the log-recorded lock — append `compact/start` before the slow work and `compact/end` after (even on failure) — so the lock is visible to replay and crash recovery.
 
 ```ts cordis-catalog
-abstract compactIfNeeded( agent: CompactAgentContext, fullSystemPrompt: string, signal: AbortSignal, ): Promise<CompactionResult | null>
+abstract compactIfNeeded( agent: CompactAgentContext, fullSystemPrompt: string, sessionPrefix: readonly Message[], signal: AbortSignal, ): Promise<CompactionResult | null>
 abstract compactRegion( session: Session, start: number, end: number, agent: CompactAgentContext, signal?: AbortSignal, ): Promise<CompactionResult>
 ```
 
-Source: [`packages/compact/compact/src/index.ts:63`](../../packages/compact/compact/src/index.ts)
+Types: [Message](../core-data-structures/core.md)
+
+Source: [`packages/compact/compact/src/index.ts:65`](../../packages/compact/compact/src/index.ts)
 
 ## `ctx.fs` — `FileSystem` (abstract seam)
 
@@ -214,7 +216,7 @@ Source: [`packages/core/system-prompt/src/index.ts:335`](../../packages/core/sys
 
 ## `ctx.tools` — `ToolRegistry`
 
-Tool registry (`ctx.tools`): tool plugins register definitions; the agent loop executes calls through the `tools/pre-execute` → dispatch → `tools/post-execute` pipeline. The registry contributes its schemas into the system-prompt assembly.
+Tool registry (`ctx.tools`): tool plugins register definitions; the agent loop executes calls through the `tools/pre-execute` → `tools/execute` → `tools/post-execute` pipeline. The registry contributes its schemas into the system-prompt assembly.
 
 Two registration layers (`@deepseek-ai/dsh-scope`): a registration through a plain plugin context is GLOBAL (visible to every agent); one through a scoped context (`agent.ctx`) is filed in that scope's layer — visible to that agent alone, disposed with the scope, and SHADOWING a global tool of the same name for that agent (most-specific-wins; within one layer a duplicate name still throws). restrict masks the global layer per scope. One visibility function (visible) feeds prompt assembly, get, and execute, so what the model is shown, what a presenter renders, and what dispatches can never disagree.
 
@@ -230,7 +232,18 @@ async execute(exec: ToolExecution): Promise<ToolExecutionResult>
 
 Types: [ToolDefinition](../core-data-structures/tools.md) · [ToolExecution](../core-data-structures/tools.md) · [ToolExecutionResult](../core-data-structures/tools.md)
 
-Source: [`packages/core/tools/src/index.ts:319`](../../packages/core/tools/src/index.ts)
+Source: [`packages/core/tools/src/index.ts:352`](../../packages/core/tools/src/index.ts)
+
+## `ctx.userInteraction` — `UserInteractionService`
+
+`ctx.userInteraction`: one active UI provider plus an `ask()` surface.
+
+```ts cordis-catalog
+registerProvider(provider: UserInteractionProvider): () => void
+async ask(request: AskUserQuestionRequest): Promise<AskUserQuestionAnswer>
+```
+
+Source: [`packages/ui/user-interaction/src/index.ts:82`](../../packages/ui/user-interaction/src/index.ts)
 
 ## `ctx.web` — `WebService`