docs,feat(doc-gates): fix 15 dead anchor fragments; verify-md-links now validates fragments

A corpus sweep under the doc/prose standards found 15 links whose #fragment
named no anchor in its target — reworded headings, one relocated contract
(tool-fs → the group README's no-timeout rule), and zh sides citing English
slugs their Chinese headings never produce. Fixed all 15 (zh sides get the
conventional explicit <a id> + English fragment), fixed the one generator-owned
instance at its source (gen-doc-graphs), and extended verify-md-links to
resolve fragments onto Markdown targets — same-file anchors included — against
heading slugs and explicit <a id>, so the class is gated instead of manually
grepped. Remaining probes (narrated history, duplication shingles, comment
transcripts, budgets) came back clean; sibling-adapter README symmetry and
implemented-note contrasts are deliberate keeps.

packages/core/tools/README.md

@@ -18,7 +18,7 @@ tools:
 ### Public API
 
 - `ctx.tools.register(definition: ToolDefinition): () => void` Register a trusted typed same-process definition with a mandatory canonical `output` declaration. The layer is the calling context's scope: a plain plugin context registers globally; an agent's `agent.ctx` registers for that agent alone, shadowing a same-named global tool there. Duplicate names within one layer throw; non-native modes also reject the reserved `run_code` transport name. Missing or unsupported output declarations and a non-positive or non-finite `timeoutMs` fail at registration. The optional synchronous `finalizeContent` callback is snapshotted when a call starts and may replace only final model-facing content after every pipeline outcome is normalized, including an error discovered while materializing another result field. Disposed with the calling fiber.
-- `ctx.tools.restrict(filter)` applies an agent-scoped allow/deny mask to global tools and throws from a plain context. The filter is snapshotted at registration; multiple masks intersect and scope-local tools merge afterwards. Deny masks admit later unnamed globals, while allow masks exclude later names. Unknown, local, or reserved names and empty filters reject. This is live visibility composition, not an authority boundary; see the [scope security non-goal](../../../.agents/notes/implemented/architecture/2026-07-08-agent-scope-contexts.md#security-and-authority-are-explicit-non-goals).
+- `ctx.tools.restrict(filter)` applies an agent-scoped allow/deny mask to global tools and throws from a plain context. The filter is snapshotted at registration; multiple masks intersect and scope-local tools merge afterwards. Deny masks admit later unnamed globals, while allow masks exclude later names. Unknown, local, or reserved names and empty filters reject. This is live visibility composition, not an authority boundary; see the [scope security non-goal](../../../.agents/notes/implemented/architecture/2026-07-08-agent-scope-contexts.md#security-and-authority-are-non-goals).
 - `ctx.tools.get(name: string, scope?: ScopeKey): ToolDefinition | undefined` Resolution as one scope sees it (shadowing applied; a restricted-away global reads as absent) — presenters pass the calling agent so the card matches what executed.
 - `ctx.tools.schemas(scope?: ScopeKey): ToolSchema[]` Schemas of everything the scope can see (without the `execute` functions). The shipped tools' schemas are catalogued in [docs/tool-catalog.md](../../../docs/tool-catalog.md), generated by booting each tool plugin and harvesting this method (see [the tool-schema-catalog Agent Note](../../../.agents/notes/implemented/process/2026-07-02-tool-schema-catalog.md)).
 - `ctx.tools.guard(guard: ToolGuard): () => void` Register a monotonic synchronous execution guard after `tools/pre-execute`: returning a reason denies the call, while `undefined` leaves it unchanged. A plain-context guard applies globally; an `agent.ctx` guard applies only to that agent. Later waterfall listeners cannot turn a guard denial back into permission. Disposed with the calling fiber.