feat(search): Add complete Search UI with API and web interface

Implements full search functionality for StarPunk v1.1.0.

Search API Endpoint (/api/search):
- GET endpoint with query parameter (q) validation
- Pagination via limit (default 20, max 100) and offset parameters
- JSON response with results count and formatted search results
- Authentication-aware: anonymous users see published notes only
- Graceful handling of FTS5 unavailability (503 error)
- Proper error responses for missing/empty queries

Search Web Interface (/search):
- HTML search results page with Bootstrap-inspired styling
- Search form with HTML5 validation (minlength=2, maxlength=100)
- Results display with title, excerpt, date, and links
- Empty state for no results
- Error state for FTS5 unavailability
- Simple pagination (Next/Previous navigation)

Navigation Integration:
- Added search box to site navigation in base.html
- Preserves query parameter on results page
- Responsive design with emoji search icon
- Accessible with proper ARIA labels

FTS Index Population:
- Added startup check in __init__.py for empty FTS index
- Automatic rebuild from existing notes on first run
- Graceful degradation if population fails
- Logging for troubleshooting

Security Features:
- XSS prevention: HTML in search results properly escaped
- Safe highlighting: FTS5 <mark> tags preserved, user content escaped
- Query validation: empty queries rejected, length limits enforced
- SQL injection prevention via FTS5 query parser
- Authentication filtering: unpublished notes hidden from anonymous users

Testing:
- Added 41 comprehensive tests across 3 test files
- test_search_api.py: 12 tests for API endpoint validation
- test_search_integration.py: 17 tests for UI rendering and integration
- test_search_security.py: 12 tests for XSS, SQL injection, auth filtering
- All tests passing with no regressions

Implementation follows architect specifications from:
- docs/architecture/v1.1.0-validation-report.md
- docs/architecture/v1.1.0-feature-architecture.md
- docs/decisions/ADR-034-full-text-search.md

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

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

starpunk/__init__.py

@@ -76,6 +76,31 @@ def create_app(config=None):
 
     init_db(app)
 
+    # Initialize FTS index if needed
+    from pathlib import Path
+    from starpunk.search import has_fts_table, rebuild_fts_index
+    import sqlite3
+
+    db_path = Path(app.config["DATABASE_PATH"])
+    data_path = Path(app.config["DATA_PATH"])
+
+    if has_fts_table(db_path):
+        # Check if index is empty (fresh migration or first run)
+        try:
+            conn = sqlite3.connect(db_path)
+            count = conn.execute("SELECT COUNT(*) FROM notes_fts").fetchone()[0]
+            conn.close()
+
+            if count == 0:
+                app.logger.info("FTS index is empty, populating from existing notes...")
+                try:
+                    rebuild_fts_index(db_path, data_path)
+                    app.logger.info("FTS index successfully populated")
+                except Exception as e:
+                    app.logger.error(f"Failed to populate FTS index: {e}")
+        except Exception as e:
+            app.logger.debug(f"FTS index check skipped: {e}")
+
     # Register blueprints
     from starpunk.routes import register_routes