Document LiveDashboard metrics in CLAUDE.md

Added section explaining available telemetry metrics including:
- Phoenix, Database, and VM metrics
- Exq background job metrics
- Redis/Valkey metrics

Includes instructions on accessing LiveDashboard

CLAUDE.md

@@ -164,6 +164,30 @@ All LiveViews, LiveComponents, and HTML modules automatically get these imports/
 - Phoenix LiveReload watches for file changes
 - Code reloader enabled via `listeners: [Phoenix.CodeReloader]`
 
+### LiveDashboard and Telemetry
+
+LiveDashboard is available at `/dashboard` (requires authentication in production, `/dev/dashboard` in development).
+
+**Available Metrics:**
+- **Phoenix Metrics**: Request duration, route timings, channel/socket metrics
+- **Database Metrics**: Query time, decode time, queue time, idle time
+- **VM Metrics**: Memory usage, run queue lengths
+- **Exq/Background Jobs**:
+  - Queue sizes (default, discovery, polling, monitoring, maintenance)
+  - Busy worker processes
+  - Total worker processes
+- **Redis/Valkey**:
+  - Connected clients
+  - Memory usage (MB)
+  - Total commands processed
+
+Metrics are collected every 10 seconds via `telemetry_poller` and published using `:telemetry.execute/3`.
+
+To view metrics:
+1. Navigate to `/dashboard` (or `/dev/dashboard` in development)
+2. Click the "Metrics" tab
+3. Scroll to see Exq and Redis sections
+
 ## Project-Specific Constraints
 
 Key constraints from AGENTS.md (see that file for complete details):