chore: track user device (#111)

* Implementation completed successfully! I've added device information capture using the `os_info` crate to the analytics service. Here's what was implemented:

1. **Added `os_info` crate dependency** to `backend/Cargo.toml`
2. **Created `get_device_info()` function** in `backend/src/services/analytics.rs:172-181` that captures:
   - Operating system type
   - OS version  
   - Architecture
   - Bitness
3. **Integrated device info** into the `track_event()` method at `backend/src/services/analytics.rs:79` so every analytics event now includes device information in the properties

The device information is now automatically included with every analytics event sent to PostHog, providing valuable context about the user's environment.

* fmt

backend/Cargo.toml

@@ -42,6 +42,7 @@ schemars = "0.8"
 regex = "1.11.1"
 notify-rust = "4.11"
 octocrab = "0.44"
+os_info = "3.12.0"
 sentry = { version = "0.41.0", features = ["anyhow", "backtrace", "panic", "debug-images"] }
 sentry-tower = "0.41.0"
 sentry-tracing = { version = "0.41.0", features = ["backtrace"] }