feat(settings): add includeGitInstructions toggle

Adds an 'Include git instructions' toggle to the Agent Settings panel.
When disabled, sets CLAUDE_CODE_DISABLE_GIT_INSTRUCTIONS=1 on the Claude
process to remove built-in commit and PR workflow guidance from its
system prompt. Resolves #209.

src-tauri/src/wsl_bridge.rs

@@ -315,6 +315,11 @@ impl WslBridge {
                 cmd.env("CLAUDE_CODE_DISABLE_CRON", "1");
             }
 
+            // Disable built-in git instructions if requested
+            if !options.include_git_instructions {
+                cmd.env("CLAUDE_CODE_DISABLE_GIT_INSTRUCTIONS", "1");
+            }
+
             cmd
         } else {
             // Running on Windows - use wsl with bash login shell to ensure PATH is loaded
@@ -372,6 +377,11 @@ impl WslBridge {
                 claude_cmd.push_str("CLAUDE_CODE_DISABLE_CRON=1 ");
             }
 
+            // Disable built-in git instructions if requested
+            if !options.include_git_instructions {
+                claude_cmd.push_str("CLAUDE_CODE_DISABLE_GIT_INSTRUCTIONS=1 ");
+            }
+
             claude_cmd.push_str(
                 "claude --output-format stream-json --input-format stream-json --verbose",
             );