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.

scripts/gen-doc-graphs.ts

@@ -1154,7 +1154,7 @@ function renderLifecycle(): string {
   const maintenance = 'curated Mermaid sequence; exact event signatures live in the generated Cordis catalog'
   return [
     ...generatedHeader('Agent Turn And Step Lifecycle'),
-    'This sequence is the visual companion to [architecture.md](architecture.md#loop-lifecycle-session--turn--step). It keeps durable replay facts on `session/event` and live control/status on `agent/*`.',
+    'This sequence is the visual companion to [architecture.md](architecture.md#default-loop-lifecycle). It keeps durable replay facts on `session/event` and live control/status on `agent/*`.',
     '',
     '```mermaid',
     'sequenceDiagram',