refactor: split skill providers

packages/core/agent-core/README.md

@@ -1,6 +1,6 @@
 # @deepseek-ai/dsh-agent-core
 
-The **providerless, executor-less, UI-less agent spine** as ONE Cordis bundle plugin. It loads the fixed set of services every harness agent needs and forwards the loop's `agents` list as its own config — so an app package composes a working agent by adding only a front door and the swappable backends.
+The **default executor-less, UI-less agent spine** as ONE Cordis bundle plugin. It loads the fixed set of services every harness agent needs, including the local skill provider, and forwards the loop's `agents` list as its own config — so an app package composes a working agent by adding only a front door and the swappable backends.
 
 This is the package to read to see **the whole plugin tree at once** — the teaching role the inlined `echo-agent` `cordis.yml` used to play before the spine moved behind this bundle.
 
@@ -14,9 +14,12 @@ This is the package to read to see **the whole plugin tree at once** — the tea
 @deepseek-ai/dsh-session          event-sourced session log + store
 @deepseek-ai/dsh-system-prompt    prompt-section + tool-schema assembly
 @deepseek-ai/dsh-tools            tool registry + tools/pre-execute/post-execute
+@deepseek-ai/dsh-skill            skill provider registry + prompt listing
+@deepseek-ai/dsh-skill-local      local filesystem skill provider
 @deepseek-ai/dsh-agent            agent registry + agent/* event vocabulary
 @deepseek-ai/dsh-invariants       dev-mode event-contract assertions
 @deepseek-ai/dsh-tool-bash        the model-facing bash/bash_output/bash_kill schemas
+@deepseek-ai/dsh-tool-skill       the model-facing skill loader schema
 @deepseek-ai/dsh-agent-loop       THE concrete loop (gets the forwarded `agents`)
                                   (dsh-system-prompt gets the forwarded `persona`)
 ```
@@ -27,6 +30,7 @@ The spine is everything COMMON to every front door. The swappable and front-door
 
 - **the LLM adapter** — the bundle ships the abstract `llm` service; the leaf registers a concrete adapter on `ctx.llm` (`llm-deepseek`, `llm-pi-ai`, `llm-replay`).
 - **the bash executor** — the bundle ships `tool-bash` (the consumer schema); the leaf provides `ctx.bash` (`bash-local` or a sandboxed impl).
+- **non-local skill providers** — the bundle ships the skill registry, the local filesystem provider, and the `skill` tool; deployments can add other providers such as embedded or remote catalogs as siblings.
 - **presentation + per-app infra** — the stdio UI / ACP bridge, a console logger, `hmr`. These form the coupled "front-door cluster" that the app packages ([`dsh-stdio-agent`](../../ui/stdio-agent/README.md), [`dsh-acp-agent`](../../ui/acp-agent/README.md)) bake in. `timer` is in the spine (common to both, stdout-silent); a console logger is NOT (it writes to stdout, which the ACP bridge reserves for JSON-RPC).
 
 This is the [interface/implementation/consumer seam](../../../docs/rfc/implemented/architecture/2026-06-13-capability-seams.md) raised to the composition level: the bundle owns the shared spine, the leaf owns the backends, the app package owns the front door.
@@ -35,11 +39,12 @@ This is the [interface/implementation/consumer seam](../../../docs/rfc/implement
 
 ```ts
 import type { Config } from '@deepseek-ai/dsh-agent-core'
-// { agents?, persona? } — the schema is z.intersect([AgentLoop.Config, SystemPrompt.Config]),
-// so validation and defaulting can never drift from the owners'.
+// { agents?, persona?, skills? } — the schema is z.intersect([AgentLoop.Config,
+// SystemPrompt.Config, { skills }]), so validation and defaulting can never
+// drift from the owners'.
 ```
 
-The bundle FORWARDS each field to the child that owns it: `agents` to `agent-loop` (default `[]`), so each app supplies its own pre-created agents — a stdio app pre-creates a `main`; the ACP app pre-creates none (it creates agents on demand at `session/new`) — and `persona` to `dsh-system-prompt` (default `''`), the deployment's persona section. Forwarding is exactly why the owners can live in the shared spine even though the apps disagree on what to configure.
+The bundle FORWARDS each field to the child that owns it: `agents` to `agent-loop` (default `[]`), so each app supplies its own pre-created agents — a stdio app pre-creates a `main`; the ACP app pre-creates none (it creates agents on demand at `session/new`) — `persona` to `dsh-system-prompt` (default `''`), and `skills.registry` / `skills.local` to the skill registry and local provider. Forwarding is exactly why the owners can live in the shared spine even though the apps disagree on what to configure.
 
 ## Why a code bundle, not a shared YAML include