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/design/v1.3.0/2025-12-10-phase3-implementation.md

@@ -0,0 +1,158 @@
+# v1.3.0 Phase 3 Implementation Report
+
+**Date**: 2025-12-10
+**Developer**: StarPunk Developer
+**Phase**: Phase 3 - Routes and Admin
+**Status**: Complete
+
+## Summary
+
+Implemented Phase 3 of the v1.3.0 microformats and tags feature as specified in `microformats-tags-design.md`. This phase adds tag support to routes and admin interfaces, completing the full tag system implementation.
+
+## Changes Implemented
+
+### 1. Public Routes (`starpunk/routes/public.py`)
+
+#### Tag Archive Route
+- **Route**: `/tag/<tag>`
+- **Functionality**:
+  - Normalizes tag parameter to lowercase before lookup
+  - Returns 404 if tag not found
+  - Loads all published notes with the specified tag
+  - Pre-loads media and tags for each note
+- **Template**: `templates/tag.html` (not created in this phase, per design doc)
+
+#### Index Route Updates
+- Pre-loads tags for each note using `object.__setattr__(note, '_cached_tags', tags)`
+- Consistent with media loading pattern
+
+#### Note Route Updates
+- Pre-loads tags for the note using `object.__setattr__(note, '_cached_tags', tags)`
+- Tags available in template via `note.tags`
+
+### 2. Admin Routes (`starpunk/routes/admin.py`)
+
+#### Create Note Route
+- Added `tags` parameter extraction from form
+- Parses comma-separated tags using `parse_tag_input()`
+- Passes tags to `create_note()` function
+- Empty tag field creates note without tags
+
+#### Edit Note Form Route
+- Pre-loads tags when loading the edit form
+- Tags available for display in form via `note.tags`
+
+#### Update Note Route
+- Added `tags` parameter extraction from form
+- Parses comma-separated tags using `parse_tag_input()`
+- Passes tags to `update_note()` function
+- Empty tag field removes all tags from note
+
+### 3. Admin Templates
+
+#### `templates/admin/edit.html`
+- Added tag input field between slug and published checkbox
+- Pre-fills with existing tags: `{{ note.tags|map(attribute='display_name')|join(', ') }}`
+- Placeholder text provides example format
+- Help text explains comma separation and blank field behavior
+
+#### `templates/admin/new.html`
+- Added tag input field between media upload and published checkbox
+- Placeholder text provides example format
+- Help text explains comma separation
+
+## Design Decisions
+
+Following the architect's Q&A responses:
+
+1. **URL normalization**: Tag route normalizes URL parameter to lowercase before lookup
+2. **Tag loading**: Pre-load using `object.__setattr__()` pattern (consistent with media)
+3. **Admin input**: Plain text field, comma-separated
+4. **Empty field behavior**: Removes all tags on update, creates without tags on create
+5. **Tag parsing**: Uses `parse_tag_input()` which handles trim, dedupe, and normalization
+
+## Testing
+
+All existing tests pass:
+- Micropub category tests pass (tags work via API)
+- Custom slug tests pass (admin routes work)
+- Microformats tests pass (templates load correctly)
+
+Only one pre-existing test failure unrelated to this implementation:
+- `test_migration_race_condition.py::TestGraduatedLogging::test_debug_level_for_early_retries`
+  - This is a logging test issue, not related to tag functionality
+
+## Files Modified
+
+1. `/home/phil/Projects/starpunk/starpunk/routes/public.py`
+   - Added tag archive route
+   - Updated index route to pre-load tags
+   - Updated note route to pre-load tags
+
+2. `/home/phil/Projects/starpunk/starpunk/routes/admin.py`
+   - Updated create route to handle tag input
+   - Updated edit form route to pre-load tags
+   - Updated update route to handle tag input
+
+3. `/home/phil/Projects/starpunk/templates/admin/edit.html`
+   - Added tag input field
+
+4. `/home/phil/Projects/starpunk/templates/admin/new.html`
+   - Added tag input field
+
+## Integration with Previous Phases
+
+This phase completes the tag system started in Phase 1 (backend) and Phase 2 (templates):
+
+- **Phase 1**: Database schema and `starpunk/tags.py` module
+- **Phase 2**: Template markup for displaying tags
+- **Phase 3**: Routes and admin integration (this phase)
+
+All three phases work together to provide:
+- Tag creation via admin interface
+- Tag creation via Micropub API (already working from Phase 1)
+- Tag display on note pages (from Phase 2)
+- Tag archive pages (new route)
+- Tag loading in all relevant routes (performance optimization)
+
+## Known Limitations
+
+Per design document:
+- No pagination on tag archive pages (acceptable for v1.3.0)
+- No tag autocomplete in admin (out of scope)
+- Tag archive template (`templates/tag.html`) not created yet (will be done in template phase)
+
+## Next Steps
+
+According to the design document, the next phase should be:
+- **Phase 4**: Validation with mf2py and indiewebify.me
+- Create `templates/tag.html` if not already created in Phase 2
+- Run microformats validation tests
+- Manual testing with indiewebify.me
+
+## Verification
+
+To verify this implementation:
+
+```bash
+# Run tests
+uv run pytest tests/test_micropub.py::test_micropub_create_with_categories -xvs
+uv run pytest tests/test_custom_slugs.py tests/test_microformats.py -xvs
+
+# Test in browser
+1. Create note via admin with tags: "Python, IndieWeb, Testing"
+2. Edit note and change tags
+3. Set tags to empty string to remove all tags
+4. View note page to see tags displayed
+5. Click tag link to view tag archive (404 until template created)
+```
+
+## Notes
+
+The implementation strictly follows the architect's design in `microformats-tags-design.md`. All decisions documented in the Q&A section were applied:
+- Tag normalization happens in route before lookup
+- Pre-loading pattern matches media loading
+- Admin forms use simple text input with comma separation
+- Empty field removes tags (explicit user action)
+
+No architectural decisions were made by the developer - all followed existing patterns and architect specifications.