fix: checker uses git diff HEAD (working tree) instead of HEAD~1..HEAD

Coder may not commit changes, so HEAD~1..HEAD misses uncommitted files.
git diff --name-only HEAD catches both staged and unstaged changes.

packages/pulse/src/workflows/roles/meta-checker.ts

@@ -41,9 +41,7 @@ export function createMetaCheckerRole(opts: {
     let changedFiles: string[] = [];
     try {
       // Get all uncommitted changes + last commit changes
-      const diffOutput = exec(
-        'git diff --name-only HEAD~1 HEAD 2>/dev/null || git diff --name-only',
-      );
+      const diffOutput = exec('git diff --name-only HEAD 2>/dev/null || git diff --name-only');
       changedFiles = diffOutput.split('\n').filter(Boolean);
     } catch {
       // No git history — check working tree