fix(cua-driver): Windows e2e convergence (conv2 2/7)

[f-trycua]

Summary

Second landing PR extracted from #2161, built on the typed evidence foundation in #2179.

• converges Windows capture, UIA caching, keyboard/pointer injection, background delivery, and recording hooks
• replaces the old UX guard/focus-monitor executable with typed cursor, launch, desktop-scope, WPF, WinUI3, WebView2, Electron, and Tauri harness coverage
• makes run-rust-e2e.ps1 the canonical all-lanes Windows entrypoint and wires independent native, shared, and capture lanes into GitHub Actions
• records every declared row as structured case/result data with source identity, side-effect oracles, trajectory JSON, screenshots when capture is available, and an owned MP4
• removes every residual focus-monitor-win reference

This PR intentionally excludes macOS, Linux/Wayland, support docs, and the independent Docker/TypeScript sidecars. The extraction plan is documented on the frozen source branch.

What this fixes

• background Windows actions no longer report success when Chromium or native controls did not receive the input
• supported WPF, WinUI3, WebView2, Electron, and Tauri routes are verified through fixture state rather than driver return values alone
• unsupported background keyboard, hotkey, scroll, drag, and occluded Chromium pointer shapes return typed, actionable refusals without focus, z-order, cursor, or leaked-input side effects
• native and shared harnesses are built from repository source during the run; no downloaded desktop fixture binaries are used
• window capture has GDI, WGC, and visible desktop-region fallbacks while preserving an honest unavailable result for minimized or non-capturable windows
• minimized-window restore is validated with before/after UIA state and video even on the hosted runner where still-image capture remains unavailable after restore

Validation

Exact source: 6d7f02e447d5a4ff638e0828780d25a86f28f77e

• Windows canonical E2E run 29211506624: all lanes and matrix summary passed
• shared Electron + Tauri: 54 delivered, 18 exact refusals, 0 failed, 0 skipped
• native WPF + WinUI3 + WebView2: 31 delivered, 3 exact refusals, 0 failed, 0 skipped
• capture + desktop scope: 8 delivered, 0 refused, 0 failed, 0 skipped
• total: 93 delivered, 21 exact refusals, 0 failed, 0 skipped across 114 rows
• each row links an owned MP4 and trajectory in the uploaded lane artifact
• Rust Windows compile/unit, Rust Linux compile/unit, Nix source, distro compatibility, docs sync, release reminder, and SPDX checks passed on the same head

Source: #2161.

[github-actions]

📦 Publishable packages changed

• cua-driver-rs

Add release:<service> labels to auto-release on merge (+ optional bump:minor or bump:major, default is patch).
Or add no-release to skip.

[github-actions]

📦 Publishable packages changed

• cua-driver-rs

Add release:<service> labels to auto-release on merge (+ optional bump:minor or bump:major, default is patch).
Or add no-release to skip.

[github-actions]

📦 Publishable packages changed

• cua-driver-rs

Add release:<service> labels to auto-release on merge (+ optional bump:minor or bump:major, default is patch).
Or add no-release to skip.

[github-actions]

📦 Publishable packages changed

• cua-driver-rs

Add release:<service> labels to auto-release on merge (+ optional bump:minor or bump:major, default is patch).
Or add no-release to skip.

[github-actions]

📦 Publishable packages changed

• cua-driver-rs

Add release:<service> labels to auto-release on merge (+ optional bump:minor or bump:major, default is patch).
Or add no-release to skip.

[github-actions]

📦 Publishable packages changed

• cua-driver-rs

Add release:<service> labels to auto-release on merge (+ optional bump:minor or bump:major, default is patch).
Or add no-release to skip.

[github-actions]

📦 Publishable packages changed

• cua-driver-rs

Add release:<service> labels to auto-release on merge (+ optional bump:minor or bump:major, default is patch).
Or add no-release to skip.

[github-actions]

📦 Publishable packages changed

• cua-driver-rs

Add release:<service> labels to auto-release on merge (+ optional bump:minor or bump:major, default is patch).
Or add no-release to skip.

[github-actions]

📦 Publishable packages changed

• cua-driver-rs

Add release:<service> labels to auto-release on merge (+ optional bump:minor or bump:major, default is patch).
Or add no-release to skip.

[github-actions]

📦 Publishable packages changed

• cua-driver-rs

Add release:<service> labels to auto-release on merge (+ optional bump:minor or bump:major, default is patch).
Or add no-release to skip.