fix(ci): create valid shell script stub for claude binary

An empty file created with `touch` is not a valid Mach-O executable.
macOS detects this invalid binary and reports the entire app as "damaged".

Replace with a proper shell script that exits cleanly.

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

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

Author: fazxes

.github/workflows/ci.yml

@@ -355,10 +355,15 @@ jobs:
           bun build ./src/index.ts --compile --target=bun-darwin-arm64 --outfile=../src-tauri/binaries/agent-bridge-aarch64-apple-darwin
           chmod +x ../src-tauri/binaries/agent-bridge-aarch64-apple-darwin
 
-      # Create placeholder for claude binary (not built in CI)
-      - name: Create claude placeholder
+      # Create a valid stub binary for claude (not built in CI)
+      # Must be a real executable, not an empty file, or macOS reports app as "damaged"
+      - name: Create claude stub binary
         run: |
-          touch src-tauri/binaries/claude-aarch64-apple-darwin
+          cat > src-tauri/binaries/claude-aarch64-apple-darwin << 'STUB'
+          #!/bin/bash
+          echo "Claude CLI stub - install the real binary for full functionality"
+          exit 0
+          STUB
           chmod +x src-tauri/binaries/claude-aarch64-apple-darwin
 
       # Build Tauri app (includes frontend build via beforeBuildCommand)