feat(tags): Add tag archive route and admin interface integration

Implement Phase 3 of v1.3.0 tags feature per microformats-tags-design.md:

Routes (starpunk/routes/public.py):
- Add /tag/<tag> archive route with normalization and 404 handling
- Pre-load tags in index route for all notes
- Pre-load tags in note route for individual notes

Admin (starpunk/routes/admin.py):
- Parse comma-separated tag input in create route
- Parse tag input in update route
- Pre-load tags when displaying edit form
- Empty tag field removes all tags

Templates:
- Add tag input field to templates/admin/edit.html
- Add tag input field to templates/admin/new.html
- Use Jinja2 map filter to display existing tags

Implementation details:
- Tag URL parameter normalized to lowercase before lookup
- Tags pre-loaded using object.__setattr__ pattern (like media)
- parse_tag_input() handles trim, dedupe, normalization
- All existing tests pass (micropub categories, admin routes)

Per architect design:
- No pagination on tag archives (acceptable for v1.3.0)
- No autocomplete in admin (out of scope)
- Follows existing media loading patterns

Generated with Claude Code

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

docs/projectplan/BACKLOG.md

@@ -0,0 +1,97 @@
+# StarPunk Backlog
+
+**Last Updated**: 2025-12-10
+
+## Priority Levels
+
+- **Critical** - Items that break existing functionality
+- **High** - Important features or fixes
+- **Medium** - Planned features
+- **Low** - Nice-to-have, deferred indefinitely
+
+---
+
+## Critical
+
+*No critical items*
+
+---
+
+## High
+
+### Strict Microformats2 Compliance
+- Complete h-entry properties (p-name, p-summary, p-author)
+- Author h-card implementation
+- h-feed wrapper for index pages
+- Full IndieWeb parser compatibility
+- Microformats2 validation suite
+- See: ADR-040
+
+### Enhanced Feed Media Support
+- Multiple image sizes/thumbnails (150px, 320px, 640px, 1280px)
+- Full Media RSS implementation (media:group, all attributes)
+- Enhanced JSON Feed attachments
+- ATOM enclosure links for all media
+- See: ADR-059
+
+### Tag/Category System
+- Database schema for tags
+- Tag-based filtering
+- Tag clouds
+- Category RSS/ATOM/JSON feeds
+- p-category microformats2 support
+
+---
+
+## Medium
+
+### Webmentions
+- Receive endpoint
+- Send on publish
+- Display received mentions
+- Moderation interface
+
+### Reply Contexts
+- In-reply-to support
+- Like/repost posts
+- Bookmark posts
+
+### Media Uploads Enhancements
+- File management interface
+- Thumbnail generation
+- CDN integration (optional)
+
+### Photo Posts
+- Instagram-like photo notes
+- Gallery views
+- EXIF data preservation
+
+### Audio/Podcast Support
+- Podcast RSS with iTunes namespace
+- Audio duration extraction
+- Episode metadata support
+- Apple/Google podcast compatibility
+- See: ADR-059
+
+### Video Support
+- Video upload handling
+- Poster image generation
+- Video in Media RSS feeds
+- HTML5 video embedding
+
+---
+
+## Low
+
+### Flaky Migration Race Condition Tests
+- Improve `test_migration_race_condition.py::TestGraduatedLogging::test_debug_level_for_early_retries`
+- Test expects DEBUG retry messages but passes when migration succeeds without retries
+- May need to mock or force retry conditions for reliable testing
+
+### Deferred Indefinitely
+- Static Site Generation - Conflicts with dynamic Micropub
+- Multi-language UI - Low priority for single-user system
+- Advanced Analytics - Privacy concerns, use external tools
+- Comments System - Use Webmentions instead
+- WYSIWYG Editor - Markdown is sufficient
+- Mobile App - Web interface is mobile-friendly