feat: add debug console for frontend and backend logs

Added a comprehensive debug console feature that captures and displays
logs from both the frontend and backend in a unified interface.

Frontend changes:
- Created DebugConsole component with real-time log display
- Added debugConsoleStore for state management and console capture
- Integrated console into main layout
- Added toggle button in StatusBar with console icon
- Implemented Ctrl+` keyboard shortcut to open/close console
- Features: log filtering by level, auto-scroll, timestamps, colour-coding

Backend changes:
- Added tracing and tracing-subscriber dependencies
- Created custom TauriLogLayer to emit Rust logs to frontend
- Integrated tracing subscriber in lib.rs setup
- Logs are forwarded via Tauri events (debug:log)

Key features:
- Circular buffer (max 1000 logs) prevents memory issues
- Frontend logs captured via console method overrides
- Backend logs forwarded from Rust tracing layer
- Log level filtering (debug, info, warn, error, all)
- Source badges distinguish frontend vs backend logs
- Colour-coded log levels for easy identification
- Auto-scroll toggle for inspecting older logs
- Clear logs button for resetting the console
- Beautiful dark-themed UI matching app aesthetic

Closes #126

src-tauri/src/debug_logger.rs

@@ -0,0 +1,78 @@
+use serde::{Deserialize, Serialize};
+use std::sync::Arc;
+use tauri::{AppHandle, Emitter};
+use tracing::{Level, Subscriber};
+use tracing_subscriber::layer::{Context, Layer};
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct DebugLogEvent {
+    pub level: String,
+    pub message: String,
+}
+
+#[derive(Clone)]
+pub struct TauriLogLayer {
+    app: Arc<AppHandle>,
+}
+
+impl TauriLogLayer {
+    pub fn new(app: AppHandle) -> Self {
+        Self {
+            app: Arc::new(app),
+        }
+    }
+}
+
+impl<S> Layer<S> for TauriLogLayer
+where
+    S: Subscriber,
+{
+    fn on_event(
+        &self,
+        event: &tracing::Event<'_>,
+        _ctx: Context<'_, S>,
+    ) {
+        let metadata = event.metadata();
+        let level = match *metadata.level() {
+            Level::ERROR => "error",
+            Level::WARN => "warn",
+            Level::INFO => "info",
+            Level::DEBUG => "debug",
+            Level::TRACE => "debug",
+        };
+
+        // Extract message from the event
+        struct MessageVisitor {
+            message: String,
+        }
+
+        impl tracing::field::Visit for MessageVisitor {
+            fn record_debug(&mut self, field: &tracing::field::Field, value: &dyn std::fmt::Debug) {
+                if field.name() == "message" {
+                    self.message = format!("{:?}", value);
+                }
+            }
+        }
+
+        let mut visitor = MessageVisitor {
+            message: String::new(),
+        };
+        event.record(&mut visitor);
+
+        // If we couldn't extract a message, try to format the whole event
+        if visitor.message.is_empty() {
+            visitor.message = metadata.name().to_string();
+        }
+
+        // Strip quotes from the message
+        let message = visitor.message.trim_matches('"').to_string();
+
+        let log_event = DebugLogEvent {
+            level: level.to_string(),
+            message,
+        };
+
+        // Emit to frontend
+        let _ = self.app.emit("debug:log", log_event);
+    }
+}