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/credentials/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/credentials/README.md
-README.md: c08831c90333f8515bf86a5af717c38c50b50817
-README.zh.md: c9756c010af5d2db0fc41f3108eabdc7f1161293
+README.md: 75e3941ff6421ca7e41a71ab2bfe8b30209ce598
+README.zh.md: d7c958689fdffc82830a82b04e2a06802bc81634

packages/credentials/README.md

@@ -10,3 +10,5 @@ The credential capability family separates reference resolution from its provide
 | [`credentials-local/`](credentials-local/README.md) | Environment and local-file provider | registers `ctx.credentials` |
 
 Configuration carries references, not secret values. Consumers resolve those references at their operation boundary; the child READMEs own mutation, precedence, and storage semantics.
+
+The subsystem reference — `CredentialRef`, per-operation resolution, UI-safe `CredentialInfo`, provider layers — is [docs/subsystems/credentials.md](../../docs/subsystems/credentials.md).

packages/credentials/README.zh.md

@@ -10,3 +10,5 @@
 | [`credentials-local/`](credentials-local/README.md) | 环境与本地文件提供方 | 注册 `ctx.credentials` |
 
 配置携带引用而非机密值。消费方在其操作边界解析这些引用；变更、优先级与存储语义由子级 README 负责。
+
+子系统参考——`CredentialRef`、按操作解析、对 UI 安全的 `CredentialInfo`、提供方层——见 [docs/subsystems/credentials.md](../../docs/subsystems/credentials.md)。