Integration automation

.github/skills/rnw-integration/README.md

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+# RNW Integration Skill
+
+Automates upgrading React Native Windows to newer upstream React Native nightly builds.
+
+## What This Skill Does
+
+This skill guides GitHub Copilot through the full RNW integration workflow — from finding the next nightly version to building and deploying the Playground app. It handles version updates, override upgrades, merge conflict resolution, and build validation.
+
+## Prerequisites
+
+Before running this skill, ensure you have:
+
+- **Node.js** >= 22 installed
+- **Yarn** package manager (the repo uses Yarn Berry / v4)
+- **Visual Studio 2022** with:
+  - C++ Desktop development workload
+  - Windows App SDK
+  - Windows 10/11 SDK
+- **Git** configured with access to:
+  - Your RNW fork (origin)
+  - `https://github.com/Microsoft/react-native-windows` (upstream)
+- **Developer Mode** enabled in Windows Settings (for app sideloading)
+
+## How to Use
+
+### Option 1: Run the Full Integration
+
+Type in VS Code Copilot Chat:
+```
+/rnw-integration run all steps
+```
+
+### Option 2: Run Specific Steps
+
+```
+/rnw-integration run step 1 to 5
+/rnw-integration run step 11
+/rnw-integration run step 12
+```
+
+### Option 3: Just Find the Next Version
+
+```
+/rnw-integration find next nightly version
+```
+
+## Steps Overview
+
+| Step | Description | Automated? |
+|------|-------------|-----------|
+| 1-5 | Find current version, calculate target date, query npm | Yes |
+| 6 | Run `yarn integrate-rn <version>` | Yes |
+| 7 | Update remaining package.json files | Yes |
+| 8 | Clean node_modules and reinstall dependencies | Yes |
+| 9 | Run `npx react-native-platform-override upgrade` | Interactive |
+| 10 | Commit changes | Yes |
+| 11 | Replace failing overrides from upstream | Yes |
+| 12 | Resolve merge conflicts (human-in-the-loop) | Per-hunk approval |
+| 13 | Update yarn.lock, build Playground composition app | Yes (long build) |
+| 14 | Deploy and launch Playground | Yes |
+
+## Key Concepts
+
+### Nightly Versions
+React Native publishes nightly builds with the format:
+```
+0.XX.0-nightly-YYYYMMDD-<commit-hash>
+```
+RNW integrates every ~7 days by advancing to a newer nightly.
+
+### Overrides
+RNW maintains platform-specific copies of upstream files (`.windows.js`, `.win32.js`). The override system tracks which upstream files are copied and detects when they change.
+
+### Merge Conflicts
+When upstream changes conflict with RNW's Windows-specific modifications, conflicts appear as `<<<<<<< Upstream` / `>>>>>>> Override` markers. Step 11 resolves these with human approval.
+
+### Conflict Resolution Patterns
+Historical patterns are documented in `references/conflict-patterns.md`. The skill uses these to propose resolutions with confidence levels (Low/Medium/High).
+
+## File Structure
+
+```
+.github/skills/rnw-integration/
+├── README.md                          # This file
+├── SKILL.md                           # Main skill instructions
+├── references/
+│   └── conflict-patterns.md           # Historical conflict resolution patterns
+└── scripts/                           # (future automation scripts)
+```
+
+## Common Issues
+
+### Build fails with "Yarn packages are out of date"
+Run `yarn install` in the repo root before building.
+
+### Build fails with missing Boost headers
+Run NuGet restore:
+```powershell
+msbuild <solution.sln> /t:Restore /p:Configuration=Debug /p:Platform=x64
+```
+
+### MSIX install fails with "No signature was present" (0x800B0100)
+Debug builds are not signed. Use loose layout registration instead:
+```powershell
+Add-AppxPackage -Register <path>\AppxManifest.xml -ForceApplicationShutdown
+```
+
+### MSBuild file locking errors (midl.exe)
+A previous build process is still running. Clean the build directory:
+```powershell
+Remove-Item -Recurse -Force vnext\build -ErrorAction SilentlyContinue
+```
+
+### Override validation fails after integration
+Run Step 10 to replace failing overrides from upstream, then Step 11 to resolve remaining conflicts.
+
+## Tips
+
+- The build (Step 12) takes 15-30 minutes for a clean build
+- When resolving conflicts, respond "Yes to all remaining" if all hunks are High confidence
+- Always check the upstream compare URL before accepting conflict resolutions
+- The major version (e.g., 0.84 → 0.85) may change between nightlies