docs: qualify plan-mode timing and workspace no-write claims

ds-review-bot round 3:
- set() after a turn's final step lands in a later turn (selection
  never forces continuation) — the same-turn phrasing overstated the
  guarantee; set() JSDoc + subsystem page (both languages).
- Workspace attach/insert/detach no-op claims now carry the
  filtered-candidate-prune caveat: mutate() durably prunes stale
  candidates even when the requested change is a no-op, a state the
  sessionIds contract explicitly permits; Workspace fence re-synced on
  both page sides; catalogs regenerated.

docs/subsystems/client-modules.md

@@ -27,7 +27,7 @@ interface WebBootEntry {
   rev: string
   /** Package-name dependency edges, informational (preflight display / HMR diffing). */
   inject?: string[]
-  /** Stage-one prefetch mark: fetch + execute (factory registration) during module-face boot. */
+  /** Stage-one prefetch mark: load the script for factory registration during module-face boot. */
   immediately?: boolean
 }
 ```