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/config/config.go

@@ -72,7 +72,8 @@ type C struct {
 	FollowsThrottlePerEvent time.Duration `env:"ORLY_FOLLOWS_THROTTLE_INCREMENT" default:"200ms" usage:"delay added per event for non-followed users"`
 	FollowsThrottleMaxDelay time.Duration `env:"ORLY_FOLLOWS_THROTTLE_MAX" default:"60s" usage:"maximum throttle delay cap"`
 
-	// Blossom blob storage service level settings
+	// Blossom blob storage service settings
+	BlossomEnabled       bool   `env:"ORLY_BLOSSOM_ENABLED" default:"true" usage:"enable Blossom blob storage server (only works with Badger backend)"`
 	BlossomServiceLevels string `env:"ORLY_BLOSSOM_SERVICE_LEVELS" usage:"comma-separated list of service levels in format: name:storage_mb_per_sat_per_month (e.g., basic:1,premium:10)"`
 
 	// Web UI and dev mode settings