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/todo/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/todo/README.md
-README.md: 66abf18131ee53d87e933757c40117841e94b07f
-README.zh.md: 38a6b3c22653b8e22cc0b693eb666620513a3d8c
+README.md: 6c7dccbbfb007737593550cea91444f8f735cf81
+README.zh.md: 3c1c35187b5111f1fdb607d70b980be57e3e79c1

packages/todo/README.md

@@ -9,3 +9,5 @@ The model-facing todo capability. It is a single **product** package because one
 | [`tool-todo/`](tool-todo/README.md) | Stores and exposes the session's todo list. | (registers on `ctx.tools`) |
 
 The child README owns the tool, persistence, and rendering contract.
+
+The event payload is documented on [docs/subsystems/session.md](../../docs/subsystems/session.md).

packages/todo/README.zh.md

@@ -9,3 +9,5 @@
 | [`tool-todo/`](tool-todo/README.md) | 存储并公开会话的 todo 列表。 | （注册到 `ctx.tools`） |
 
 子级 README 负责工具、持久化和渲染契约。
+
+事件载荷记录在 [docs/subsystems/session.md](../../docs/subsystems/session.md)。