Fix web UI not showing cached events and add Blossom toggle (v0.48.13)

- Fix fetchEvents() discarding IndexedDB cached events instead of merging with relay results
- Add mergeAndDeduplicateEvents() helper to combine and dedupe events by ID
- Add ORLY_BLOSSOM_ENABLED config option to disable Blossom server
- Make fetch-kinds.js fall back to existing eventKinds.js when network unavailable

Files modified:
- app/web/src/nostr.js: Fix event caching, add merge helper
- app/web/scripts/fetch-kinds.js: Add fallback for network failures
- app/config/config.go: Add BlossomEnabled config field
- app/main.go: Check BlossomEnabled before initializing Blossom server
- pkg/version/version: Bump to v0.48.13

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

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

app/main.go

@@ -435,7 +435,7 @@ func Run(
 
 	// Initialize Blossom blob storage server (only for Badger backend)
 	// MUST be done before UserInterface() which registers routes
-	if badgerDB, ok := db.(*database.D); ok {
+	if badgerDB, ok := db.(*database.D); ok && cfg.BlossomEnabled {
 		log.I.F("Badger backend detected, initializing Blossom server...")
 		if l.blossomServer, err = initializeBlossomServer(ctx, cfg, badgerDB); err != nil {
 			log.E.F("failed to initialize blossom server: %v", err)
@@ -445,6 +445,8 @@ func Run(
 		} else {
 			log.W.F("blossom server initialization returned nil without error")
 		}
+	} else if !cfg.BlossomEnabled {
+		log.I.F("Blossom server disabled via ORLY_BLOSSOM_ENABLED=false")
 	} else {
 		log.I.F("Non-Badger backend detected (type: %T), Blossom server not available", db)
 	}