feat: v1.2.0-rc.1 - IndieWeb Features Release Candidate

Complete implementation of v1.2.0 "IndieWeb Features" release.

## Phase 1: Custom Slugs
- Optional custom slug field in note creation form
- Auto-sanitization (lowercase, hyphens only)
- Uniqueness validation with auto-numbering
- Read-only after creation to preserve permalinks
- Matches Micropub mp-slug behavior

## Phase 2: Author Discovery + Microformats2
- Automatic h-card discovery from IndieAuth identity URL
- 24-hour caching with graceful fallback
- Never blocks login (per ADR-061)
- Complete h-entry, h-card, h-feed markup
- All required Microformats2 properties
- rel-me links for identity verification
- Passes IndieWeb validation

## Phase 3: Media Upload
- Upload up to 4 images per note (JPEG, PNG, GIF, WebP)
- Automatic optimization with Pillow
  - Auto-resize to 2048px
  - EXIF orientation correction
  - 95% quality compression
- Social media-style layout (media top, text below)
- Optional captions for accessibility
- Integration with all feed formats (RSS, ATOM, JSON Feed)
- Date-organized storage with UUID filenames
- Immutable caching (1 year)

## Database Changes
- migrations/006_add_author_profile.sql - Author discovery cache
- migrations/007_add_media_support.sql - Media storage

## New Modules
- starpunk/author_discovery.py - h-card discovery and caching
- starpunk/media.py - Image upload, validation, optimization

## Documentation
- 4 new ADRs (056, 057, 058, 061)
- Complete design specifications
- Developer Q&A with 40+ questions answered
- 3 implementation reports
- 3 architect reviews (all approved)

## Testing
- 56 new tests for v1.2.0 features
- 842 total tests in suite
- All v1.2.0 feature tests passing

## Dependencies
- Added: mf2py (Microformats2 parser)
- Added: Pillow (image processing)

Version: 1.2.0-rc.1

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

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

templates/admin/edit.html

@@ -23,6 +23,20 @@
       <small>Use Markdown syntax for formatting</small>
     </div>
 
+    <div class="form-group">
+      <label for="slug">Slug (permanent)</label>
+      <input type="text"
+             id="slug"
+             name="slug"
+             value="{{ note.slug }}"
+             readonly
+             class="form-control"
+             disabled>
+      <small class="form-text text-muted">
+        Slugs cannot be changed after creation to preserve permalinks.
+      </small>
+    </div>
+
     <div class="form-group form-checkbox">
       <input type="checkbox" id="published" name="published" {% if note.published %}checked{% endif %}>
       <label for="published">Published</label>