Set up AI dev environment for recordingtest (#2)

- CLAUDE.md with collaboration rules and Planner/Generator/Evaluator cycle
- .claude/ agents, commands, skills, hooks per Claude Code conventions
- Sprint Contracts for sut-prober, normalizer, recorder, player, diff-reporter
- SUT catalog (EG-BIM Modeler, 187 plugins) and .gitignore excluding SUT tree
- PROGRESS.md / PLAN.md as shared agent handoff state
- Solution scaffold targeting sut-prober PoC

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.claude/skills/flaui-cookbook/SKILL.md

@@ -0,0 +1,53 @@
+---
+name: flaui-cookbook
+description: FlaUI and UI Automation recipes for the recordingtest project — waiting strategies, element finding patterns, pattern invocation, and integration with element-aware recording. Use when writing recorder/player code or diagnosing flaky UIA interactions.
+---
+
+# FlaUI cookbook
+
+## Dependencies
+- `FlaUI.Core`, `FlaUI.UIA3` (prefer UIA3 over UIA2)
+- Target: `net8.0-windows` or higher
+
+## Launching the SUT
+
+```csharp
+var app = FlaUI.Core.Application.Launch("EG-BIM Modeler/EG-BIM Modeler.exe");
+using var automation = new UIA3Automation();
+var main = app.GetMainWindow(automation, TimeSpan.FromSeconds(30));
+```
+
+## Finding elements (prefer AutomationId > Name > ClassName)
+
+```csharp
+var btn = main.FindFirstDescendant(cf => cf.ByAutomationId("BoxCommand")).AsButton();
+```
+
+## Waiting — NEVER use fixed sleep
+
+```csharp
+Retry.WhileNull(
+    () => main.FindFirstDescendant(cf => cf.ByName("Ready")),
+    timeout: TimeSpan.FromSeconds(10),
+    interval: TimeSpan.FromMilliseconds(100));
+```
+
+For plugin load completion, wait on a known UIA element from a late-loading plugin, not a timer.
+
+## Element path capture (for element-aware recording)
+
+Walk ancestors and emit `ClassName[@AutomationId='…']/ClassName[@Name='…']` — resilient to layout changes.
+
+## 3D viewport fallback
+
+SharpDX D3D11 surface is a UIA dead zone. Record:
+1. The hosting element's UIA path
+2. A normalized offset `(dx/width, dy/height)` inside that element
+3. The engine state sidecar AFTER the interaction
+
+## Common pitfalls
+
+- Calling UIA from the wrong thread — always marshal to STA.
+- Stale cached elements after modal dialogs — re-find after focus change.
+- IME composition swallows keys — use clipboard paste for Korean/Japanese input.
+- MahApps Flyouts are not descendants of MainWindow; search from the desktop root.