Link support codes to agent sessions

- Server: Accept support_code param in WebSocket connection
- Server: Link code to session when agent connects, mark as connected
- Server: Mark code as completed when agent disconnects
- Agent: Accept support code from command line argument
- Agent: Send hostname and support_code in WebSocket params
- Portal: Trigger agent download with code in filename
- Portal: Show code reminder in download instructions
- Dashboard: Add machines list fetching (Access tab)
- Add TODO.md for feature tracking

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

agent/src/main.rs

@@ -1,6 +1,12 @@
 //! GuruConnect Agent - Remote Desktop Agent for Windows
 //!
 //! Provides screen capture, input injection, and remote control capabilities.
+//!
+//! Usage:
+//!   guruconnect-agent.exe [support_code]
+//!
+//! If a support code is provided, the agent will connect using that code
+//! for a one-time support session.
 
 mod capture;
 mod config;
@@ -28,8 +34,25 @@ async fn main() -> Result<()> {
 
     info!("GuruConnect Agent v{}", env!("CARGO_PKG_VERSION"));
 
+    // Parse command line arguments
+    let args: Vec<String> = std::env::args().collect();
+    let support_code = if args.len() > 1 {
+        let code = args[1].trim().to_string();
+        // Validate it looks like a 6-digit code
+        if code.len() == 6 && code.chars().all(|c| c.is_ascii_digit()) {
+            info!("Support code provided: {}", code);
+            Some(code)
+        } else {
+            info!("Invalid support code format, ignoring: {}", code);
+            None
+        }
+    } else {
+        None
+    };
+
     // Load configuration
-    let config = config::Config::load()?;
+    let mut config = config::Config::load()?;
+    config.support_code = support_code;
     info!("Loaded configuration for server: {}", config.server_url);
 
     // Run the agent