docs: anchor each subsystem page to its package group; make group READMEs thin tables

core.md read as a type grab-bag: LLM wire vocabulary up front, the agent/loop story buried, and no correspondence to packages/core. It now opens on the packages/core control spine — the package-by-package loop map with a Page column into session/system-prompt/tools/scope — and keeps only what the spine group declares plus the repo-wide patterns: the Agent handle with its delivery/cancellation/interception contracts, the SessionEvent envelope, branded ids, the …Map pattern. The conversation vocabulary (Message/ContentBlock, the model request, adapters — 17 type-equiv blocks) moves to llm-streaming.md, which now declares packages/llm end-to-end; the duplicate ContentBlockMap paste near its seam section folds into the moved section, and the manifest, LINK_MAP, README table rows, website label (Core data structures → Core), and inbound anchors follow.

Every packages/<group>/README pair is now a thin front door in one shape: a why-first intro (bash's seam-pattern-first paragraph rewritten as 'shell execution for the agent'), the package table, and a closing pointer to the owning docs/subsystems page — the bash-style table stays the load-bearing middle. Load-bearing trailing paragraphs relocate rather than vanish: the fs no-timeout rationale becomes a filesystem.md section (both languages), session's four sectioned tables merge into one 12-row table, examples' legacy-bin H2 collapses to a pointer at jsonrpc-demo's README, and design rationale that already lives in an Agent Note or subsystem page is now linked instead of restated. All 40 pair records re-recorded.

packages/skill/README.i18n.yaml

@@ -2,5 +2,5 @@
 # side as of the last confirmed-consistent state. Both languages carry equal authority;
 # after editing either side, bring the other along and re-record with:
 #   pnpm run verify-translation-pairing --write packages/skill/README.md
-README.md: 533904859ad998de4f371a073fde98b68660097b
-README.zh.md: 1fad581cc61a05251f671577dcb7edab37281283
+README.md: cd606e778335249bf8ecc876d3b1a4e5feb79448
+README.zh.md: 4db7e2524596f4c62144ec7eabe7c6af63e2e270

packages/skill/README.md

@@ -12,3 +12,5 @@ This family discovers reusable agent instructions and exposes them to the model
 | [`tool-skill/`](tool-skill/README.md) | Publishes the skill catalog and model-facing loader | registers on `ctx.tools` |
 
 This capability remains outside the core control spine and can use local, embedded, or remote providers without changing the model-facing contract.
+
+The subsystem reference — discovery priority, catalog snapshots, the `skill` loader — is [docs/subsystems/skills.md](../../docs/subsystems/skills.md).

packages/skill/README.zh.md

@@ -12,3 +12,5 @@
 | [`tool-skill/`](tool-skill/README.md) | 发布 skill 目录和面向模型的 loader | 注册到 `ctx.tools` |
 
 该能力位于核心控制主干之外，可以使用本地、嵌入式或远程提供方，而无需更改面向模型的契约。
+
+子系统参考——发现优先级、目录快照、`skill` 加载器——见 [docs/subsystems/skills.md](../../docs/subsystems/skills.md)。