build: verify local changes skill

Firestore/.agents/skills/verify-local-changes/SKILL.md

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+---
+name: Verify Local Changes
+description: Verifies local Firebase iOS SDK changes.
+---
+
+# Verify Local Changes (iOS/Apple)
+
+This skill documents how to verify local code changes for the Firebase Apple SDKs using command-line tools.
+
+## Prerequisites
+
+- Xcode 16.2+
+- CocoaPods 1.12.0+
+- `cocoapods-generate` plugin
+
+---
+
+## Step 0: Format and Style
+
+Run the style script before creating a PR:
+
+```bash
+./scripts/check.sh --allow-dirty
+```
+
+---
+
+## Step 1: Boot the iOS Simulator
+
+Ensure that an iOS Simulator is booted and ready to run tests.
+
+```bash
+# List available simulators and find their status
+xcrun simctl list devices | grep "iPhone 16"
+
+# Boot the simulator (e.g., "iPhone 16" for Xcode 16)
+xcrun simctl boot "iPhone 16"
+```
+
+---
+
+## Step 2: Install Dependencies (CocoaPods)
+
+Generate the CocoaPods workspace targeting the iOS platform:
+
+```bash
+PLATFORM=iOS pod update --project-directory=Firestore/Example
+```
+
+---
+
+## Step 3: Build and Run Unit Tests
+
+Use `xcodebuild` to build and run the unit tests.
+
+### Build Unit Tests:
+```bash
+xcodebuild \
+  -workspace Firestore/Example/Firestore.xcworkspace \
+  -scheme Firestore_Tests_iOS \
+  -destination "platform=iOS Simulator,name=iPhone 16" \
+  -jobs 4 \
+  build-for-testing
+```
+
+### Run Unit Tests:
+```bash
+xcodebuild \
+  -workspace Firestore/Example/Firestore.xcworkspace \
+  -scheme Firestore_Tests_iOS \
+  -destination "platform=iOS Simulator,name=iPhone 16" \
+  test-without-building
+```
+
+---
+
+## Step 4: Build and Run Integration Tests (Emulator)
+
+The integration tests run against the Cloud Firestore emulator. The build/test scripts automatically manage the emulator lifecycle.
+
+### Build Integration Tests:
+```bash
+scripts/build.sh Firestore iOS xcodebuild
+```
+
+### Run Integration Tests:
+```bash
+scripts/build.sh Firestore iOS xcodetest
+```
+
+---
+
+> [!IMPORTANT]
+> Running `scripts/build.sh` might modify Xcode project files. Revert these changes before creating a PR.