feat(ctx7): coverage extension — fast-libs single source + reminder hook + executor briefs (BDR-078)

- lib/fast-libs.sh: detect/cache-status verbs, JS+Python manifests,
  7-day cache freshness, LC_ALL=C sort — replaces 3 hardcoded lists
  (ship-feature 0c, init-project 5c, onboard 3.5)
- hooks/ctx7-reminder.sh: once-per-session UserPromptSubmit nudge when
  the project carries fast-libs and .ctx7-cache/ is missing/stale
- find-docs: before-writing-code trigger + cache-first rule; dist is
  machine-owned (gitignored) so the durable patch lives in
  install-plugins.sh STEP ctx7 (idempotent, grep-guarded)
- feater/bugfixer briefs: fast-lib docs rule (fresh cache read, else
  2-topic ctx7 fetch, else NOTES cache miss + proceed)
- tests: lib/tests/fast-libs.test.sh (11 checks); shellcheck + full
  make test green (review-guards 5/0)

skills/ship-feature/SKILL.md

@@ -52,7 +52,8 @@ ls .gsd/ROADMAP.md 2>/dev/null | head -1
   STOP.
 
 ## STEP 0c — CTX7 CACHE CHECK (if fast-libs in project)
-Check if the project uses fast-evolving libs (scan `package.json` for next, react, prisma, supabase, drizzle, expo):
+Check if the project uses fast-moving libs — single source of truth:
+`bash ~/.claude/lib/fast-libs.sh detect .` (exit 1 = none; BDR-078):
 1. If `.ctx7-cache/` exists with recent files (<7 days old) → print `📚 ctx7 cache found: <libs>` and continue.
 2. If `.ctx7-cache/` missing or stale AND `ctx7` is installed AND fast-libs detected:
    ```bash