feat(flow): add structured YAML selectors and property assertions

[qmkCamel]

Summary

This PR adds a deterministic accessibility-tree lane to YAML flows while preserving the existing natural-language/vision lane:

• select elements by exact/contains/regex text, id, accessibilityId, type, hint, or value
• disambiguate by state, index, spatial relations, and accessibility-tree relations
• use structured targets from tap, type, wait, swipe, scroll, and assertion steps
• assert element presence, state, content, count, dimensions, and coordinates with actionable selector diagnostics
• retain selector diagnostics in reports, including redaction for password values

Structured targets fail deterministically when the accessibility tree cannot resolve them; they do not silently fall back to vision. Existing semantic string targets remain backward compatible.

- tap:
    target:
      id: com.example:id/search
      enabled: true
      clickable: true

- assert:
    target:
      id: com.example:id/submit
      rightOf:
        id: com.example:id/editor
    properties:
      visible: true
      enabled: true
      width:
        gte: 120

Android stability fixes

Real-device validation exposed two Android-specific gaps that are included here:

• keep stable resource-id nodes even when UiAutomator2 reports them as non-clickable or without accessible text
• apply UiAutomator2 idle/selector/action timeouts through the post-session settings endpoint instead of invalid session capabilities

This makes id-only child containers addressable and prevents dynamic apps from waiting for an idle accessibility tree before each page-source read.

Compatibility

• preserves the v2.2.0 anchored scrollAssert target/target-proximity behavior from feat: Feat/anchored scroll assert #55
• adds a focused regression for scrollAssert using both a structured selector and an anchored target
• keeps legacy string YAML syntax and semantic/vision execution unchanged

Documentation

• README examples and feature overview
• docs/structured-selectors.md selector/assertion reference and migration guidance
• docs/runner-architecture.md Android hierarchy and post-session settings details
• OpenSpec change fix-android-structured-selector-device-stability

Validation

• npm run typecheck
• npm test — 24 files, 448 tests passed
• npm run format:check
• openspec validate fix-android-structured-selector-device-stability --strict
• focused flow compatibility suite — 44 tests passed
• Android physical device, OnePlus 8T / Android 14 / Kuaishou com.smile.gifmaker: 8/8 steps passed; compound selectors, state/geometry assertions, and rightOf relation verified (20260811T091013-9f73ee)
• iOS physical device, iPhone 16 Plus / iOS 26.2.1 / Kuaishou com.kwai.gif.qmk.edge: two 8/8 structured-flow runs passed before the v2.2.0 rebase (20260811T083033-e6c872, 20260811T083117-0a7d83)

The post-rebase range-diff retains the Android fix unchanged; the only integration delta is preserving both the upstream anchored-scroll arguments and the new structured selector, covered by the focused compatibility test above.

[github-actions]

🎉 This PR is included in version 2.3.0 🎉

The release is available on:

• v2.3.0
• GitHub release

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