feat: Implement Phase 4 Web Interface with bugfixes (v0.5.2)

## Phase 4: Web Interface Implementation

Implemented complete web interface with public and admin routes,
templates, CSS, and development authentication.

### Core Features

**Public Routes**:
- Homepage with recent published notes
- Note permalinks with microformats2
- Server-side rendering (Jinja2)

**Admin Routes**:
- Login via IndieLogin
- Dashboard with note management
- Create, edit, delete notes
- Protected with @require_auth decorator

**Development Authentication**:
- Dev login bypass for local testing (DEV_MODE only)
- Security safeguards per ADR-011
- Returns 404 when disabled

**Templates & Frontend**:
- Base layouts (public + admin)
- 8 HTML templates with microformats2
- Custom responsive CSS (114 lines)
- Error pages (404, 500)

### Bugfixes (v0.5.1 → v0.5.2)

1. **Cookie collision fix (v0.5.1)**:
   - Renamed auth cookie from "session" to "starpunk_session"
   - Fixed redirect loop between dev login and admin dashboard
   - Flask's session cookie no longer conflicts with auth

2. **HTTP 404 error handling (v0.5.1)**:
   - Update route now returns 404 for nonexistent notes
   - Delete route now returns 404 for nonexistent notes
   - Follows ADR-012 HTTP Error Handling Policy
   - Pattern consistency across all admin routes

3. **Note model enhancement (v0.5.2)**:
   - Exposed deleted_at field from database schema
   - Enables soft deletion verification in tests
   - Follows ADR-013 transparency principle

### Architecture

**New ADRs**:
- ADR-011: Development Authentication Mechanism
- ADR-012: HTTP Error Handling Policy
- ADR-013: Expose deleted_at Field in Note Model

**Standards Compliance**:
- Uses uv for Python environment
- Black formatted, Flake8 clean
- Follows git branching strategy
- Version incremented per versioning strategy

### Test Results

- 405/406 tests passing (99.75%)
- 87% code coverage
- All security tests passing
- Manual testing confirmed working

### Documentation

- Complete implementation reports in docs/reports/
- Architecture reviews in docs/reviews/
- Design documents in docs/design/
- CHANGELOG updated for v0.5.2

### Files Changed

**New Modules**:
- starpunk/dev_auth.py
- starpunk/routes/ (public, admin, auth, dev_auth)

**Templates**: 10 files (base, pages, admin, errors)
**Static**: CSS and optional JavaScript
**Tests**: 4 test files for routes and templates
**Docs**: 20+ architectural and implementation documents

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

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

starpunk/routes/public.py

@@ -0,0 +1,57 @@
+"""
+Public routes for StarPunk
+
+Handles public-facing pages including homepage and note permalinks.
+No authentication required for these routes.
+"""
+
+from flask import Blueprint, abort, render_template
+
+from starpunk.notes import list_notes, get_note
+
+# Create blueprint
+bp = Blueprint("public", __name__)
+
+
+@bp.route("/")
+def index():
+    """
+    Homepage displaying recent published notes
+
+    Returns:
+        Rendered homepage template with note list
+
+    Template: templates/index.html
+    Microformats: h-feed containing h-entry items
+    """
+    # Get recent published notes (limit 20)
+    notes = list_notes(published_only=True, limit=20)
+
+    return render_template("index.html", notes=notes)
+
+
+@bp.route("/note/<slug>")
+def note(slug: str):
+    """
+    Individual note permalink page
+
+    Args:
+        slug: URL-safe note identifier
+
+    Returns:
+        Rendered note template with full content
+
+    Raises:
+        404: If note not found or not published
+
+    Template: templates/note.html
+    Microformats: h-entry
+    """
+    # Get note by slug
+    note_obj = get_note(slug=slug)
+
+    # Return 404 if note doesn't exist or isn't published
+    if not note_obj or not note_obj.published:
+        abort(404)
+
+    return render_template("note.html", note=note_obj)