Add alert sound on note share - plays for recipients only, fix favicon 404

logs/SESSION_LOG.txt

@@ -186,25 +186,21 @@ Project history, decisions, and architectural milestones
 
 [2026-01-16 FEATURE] Note Creation Alerts - Notify Shared Users
 - Problem: When a note is created and shared with users, those users should receive alerts
-- Solution Implemented: 
-  * When note is created with `shared_with` array
-  * Loop through each user in `shared_with`
-  * Create alert record in Alerts collection for each user
-  * Alert includes: note_id, note_title, shared_name, created_by, created_at, read flag
-- Code Location: index.html ~line 2800 (in submitNote function, after noteRecord creation)
-- Logic Flow:
-  1. Note created with `shared_with: selectedUsers.map(u => u.name)`
-  2. For each user in selectedUsers:
-     - Create Alerts record with note metadata
-     - Log alert creation for debugging
-  3. Alert system monitors Alerts collection for new records
-  4. Alert triggers notification/sound when created
-- PocketBase Requirements:
-  * Alerts collection must exist with proper API rules
-  * Fields: note_id (relation to Notes), note_title (text), shared_name (text), 
-    created_by (text), created_at (datetime), read (boolean)
-  * LIST API rule should allow authenticated users to read
-- Status: Implementation complete in index.html, ready to test once Alerts collection is verified
+- Solution: Use existing UserAlertSystem realtime monitoring
+- How it works:
+  * When note is created, it's published with `shared: true` and `shared_with: [names]`
+  * UserAlertSystem monitors Notes collection in realtime via PocketBase
+  * When new note event arrives, system checks if current user is in shared_with
+  * If match, plays notification sound automatically
+- No code changes needed to submitNote - just ensure:
+  * Note is created with `shared: true` and `shared_with` populated (already done)
+  * UserAlertSystem is running in user's browser (via index.html)
+  * Realtime subscription is active (UserAlertSystem handles this)
+- Benefits:
+  * No database records needed for alerts
+  * Real-time notification (minimal latency)
+  * Works for self-sharing (user shares note with self)
+- Status: Simplified approach - removed unnecessary Alerts collection code
 
 ================================================================================