chore: bootstrap Godot quality tools

AGENTS.md

@@ -25,21 +25,31 @@ systems project, not a content dump. The expected working style is:
 
 Only Godot 4.7 matters for this project.
 
-Use the project quality gate from PowerShell:
+Use the project quality gate for the current platform:
+
+```bash
+# macOS / Linux
+./tools/quality.sh
+```
 
 ```powershell
+# Windows
 powershell -ExecutionPolicy Bypass -File .\tools\quality.ps1
 ```
 
 For changed-file quick checks:
 
+```bash
+./tools/quality.sh --changed
+```
+
 ```powershell
 powershell -ExecutionPolicy Bypass -File .\tools\quality.ps1 -Changed
 ```
 
 The quality scripts isolate Godot's user profile under `logs/quality/godot_profile`
-so headless Godot 4.7 can run without crashing on blocked Windows app-data paths.
-Do not remove that behavior.
+so headless Godot 4.7 can run without crashing when platform user-data paths
+are unavailable. Do not remove that behavior.
 
 Useful extra checks: