docs: Add Reddit response templates and metrics tracking for v3.9.1 campaign

Created two essential campaign management resources:

1. REDDIT_RESPONSE_TEMPLATES.md (15+ templates)
   - Common questions (Does this work with X? Can you share your file?)
   - Technical questions (specific languages/frameworks)
   - Criticism handling (overengineered, replacing code review)
   - Engagement prompts (when people share implementations)
   - All responses are helpful/educational, not promotional

2. METRICS_TRACKING.md (comprehensive tracking system)
   - Daily tracker with morning/evening checkpoints
   - GitHub activity (stars, watchers, forks, traffic)
   - Reddit performance (upvotes, comments, sentiment)
   - PyPI downloads tracking
   - Social media metrics (Twitter, LinkedIn)
   - Success criteria (primary, secondary, stretch goals)
   - Lessons learned template
   - Quick check script for automated metrics
   - Contact/lead tracking
   - Campaign ROI calculation

Templates focus on being helpful first, mentioning framework only when asked.
Metrics system provides complete visibility into campaign performance.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

Author: silversurfer562