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/init-project/SKILL.md

@@ -114,7 +114,9 @@ report carries the rendered README draft as `[CREATE-AUTO]`; re-dispatch
 that plan to write it. No stop (README bootstrap is unconditional).
 
 ## STEP 5c — CTX7 PRE-FETCH (if fast-libs detected)
-If `fast-libs` signal was detected in STEP 0 (Next.js, React 18+, Prisma, Supabase, Drizzle, etc.):
+If `fast-libs` signal was detected in STEP 0 — single source of truth:
+`bash ~/.claude/lib/fast-libs.sh detect .` (Next.js, React, Prisma,
+Supabase, Drizzle… — BDR-078):
 1. Create `.ctx7-cache/` directory in project root.
 2. For each detected fast-lib, fetch core docs:
    ```bash