Fix remaining critical, high, and medium issues from 4-perspective review

Critical fixes:
- Fix rating clamp range 1-10 → 1-5 (actual scale)
- Add `ietf ideas convergence` command (SequenceMatcher at 0.75 threshold)
- Fix "628 cross-org ideas" → 130 (verified from current DB) across 8 files

Security fixes:
- Sanitize FTS5 query input (strip special chars + boolean operators)
- Add rate limiting (10 req/min/IP) on Claude-calling endpoints
- Change <path:name> → <string:name> on draft routes

Codebase fixes:
- Add Database context manager (__enter__/__exit__)
- Wire false_positive filtering into queries (exclude by default in web UI)
- Fix Post 3 arithmetic ("~300" → "~409" distinct proposals)

Content & licensing:
- Add MIT LICENSE file
- Add IPR/FRAND notes (BCP 79, RFC 8179) to Posts 03 and 07
- Qualify "4:1 safety ratio" with monthly variation in 6 remaining files
- Add "Data as of March 2026" freeze-date headers to all 10 blog posts
- Hedge causal language in Post 04

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

CLAUDE.md

@@ -61,6 +61,8 @@ When working as a team:
 3. **Coder** implements new features following existing patterns (Click CLI, SQLite, rich output)
 4. **Writer** produces the blog series from data packages and architectural guidance
 
+**Always launch agents in parallel when possible.** If agents have independent tasks (e.g., Analyst querying data while Writer drafts from existing material, or Coder implementing features that don't depend on each other), spawn them concurrently in a single message rather than sequentially. Only run agents sequentially when one genuinely depends on another's output.
+
 All agents should:
 - Read `scripts/agent-team-prompt.md` for the full brief
 - Log milestones to `data/reports/dev-journal.md`