docs: add comprehensive quality and operational guidance

Added 10 major improvements covering quality, performance, and operations:

HIGH PRIORITY (Common Pain Points):

1. **Handling Copilot Review Comments** (60 lines)
   - Prioritize by severity (security > bugs > quality > style)
   - Validate accuracy before changing (false positives)
   - When to address automatically vs ask user
   - Handling multiple comments and conflicts with requirements

2. **Failed CI After Push** (50 lines)
   - What to do when CI fails (was missing)
   - How to fix linting, tests, and build failures locally
   - When to ask user for help

3. **Post-Merge Production Verification** (65 lines)
   - Wait for deployment, verify artifacts
   - Basic smoke tests and monitoring
   - What to check and when
   - How to handle issues detected

4. **Squashing Commit History** (60 lines)
   - When to squash vs preserve commits
   - Three methods: squash merge, interactive rebase, reset
   - Default approach guidance

MEDIUM PRIORITY (Quality Improvements):

5. **Dependency Update Strategy** (55 lines)
   - Safe update process
   - Check changelogs, test thoroughly
   - Document major updates
   - When to update vs when not to

6. **Performance Checks** (75 lines)
   - Database query optimization
   - Asset size checks
   - PageSpeed/Lighthouse testing
   - Query Monitor usage

7. **Accessibility Basics** (85 lines)
   - Keyboard navigation, screen readers
   - Semantic HTML, alt text, color contrast
   - Form labels, WCAG compliance
   - When to do thorough testing

8. **SEO Considerations** (95 lines)
   - Meta tags, heading hierarchy
   - URL structure, structured data
   - Image optimization, internal linking
   - Quick SEO checks

LOWER PRIORITY (Specific Scenarios):

9. **Incident Communication** (75 lines)
   - Assess severity (P0/P1/P2)
   - Who to notify and when
   - Progress updates during incidents
   - Post-mortem documentation

10. **Multisite WordPress** (55 lines)
    - Network-wide vs site-specific changes
    - Testing on multisite
    - Deployment considerations

TOTAL ADDITIONS:
- +675 lines of guidance
- File: 1,807 → 2,478 lines (+37% growth)

These additions address common quality issues, improve operational
procedures, and provide clear guidance for complex scenarios.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: codepuncher