fix: Sidebar toggle positioning and documentation updates

- Fix collapsible sidebar toggle button positioning (moved outside sidebar)
- Toggle button now stays visible when sidebar is collapsed
- Update cache busting version
- Update Claude.md with new features documentation
- Update README.md with new features documentation
- Remove migrations folder (no longer needed)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

migrations/008_ticket_visibility.sql

@@ -1,15 +0,0 @@
--- Migration: Add ticket visibility levels
--- Run this migration to enable ticket visibility features
-
--- Add visibility columns to tickets table
-ALTER TABLE tickets
-ADD COLUMN visibility ENUM('public', 'internal', 'confidential') DEFAULT 'public' AFTER type,
-ADD COLUMN visibility_groups VARCHAR(500) DEFAULT NULL AFTER visibility;
-
--- Create index for visibility filtering
-CREATE INDEX idx_tickets_visibility ON tickets(visibility);
-
--- Example usage:
--- Public: All authenticated users can see the ticket
--- Internal: Only users in specified groups can see the ticket (visibility_groups contains comma-separated group names)
--- Confidential: Only creator, assignee, and admins can see the ticket