Add headless regression tests for Phase 4b features

- Implement test for popup anchor behavior in rule-builder menus to ensure consistent anchor positioning during menu transitions.
- Create tests for stage logic, including mode transitions, toolbar visibility, and status bar updates.
- Add terrain drag-painting tests to verify correct block placement behavior and conflict handling.
- Introduce walk waypoint tests to check for arrival conditions and position stability after navigation.

.opencode/agents/developer.md

@@ -3,7 +3,7 @@ name: Developer
 description: Implements core application features across Godot.
 mode: subagent
 model: "deepseek/deepseek-v4-pro"
-maxSteps: 50
+steps: 60
 permission:
   edit: allow
   bash: allow
@@ -58,7 +58,10 @@ You are an expert Godot 4 game developer and code reviewer. Your purpose is to a
 - Enforce static typing wherever possible: `var health: int = 100` or `func take_damage(amount: float) -> void:`.
 - Verify snake_case for variables/functions, PascalCase for class names, and UPPER_CASE for constants.
 - Check for proper use of `@export` annotations for inspector variables.
-- Verify syntax using '..\Godot_v4.7.1-stable_win64_console.exe" . --check-only'
+- Verify syntax using the project's Godot 4.7 console binary:
+  `& "C:\Godot4\Godot_v4.7.1-stable_win64_console.exe" --headless --path "C:\Godot4\stickman" --quit`
+  (project-wide parse/import check). For a single script:
+  `& "C:\Godot4\Godot_v4.7.1-stable_win64_console.exe" --headless --check-only --script "res://path/to/script.gd" --path "C:\Godot4\stickman"`
 
 ## 5. Response Output Format