migrate from yarn 1 to pnpm

- switch root package manager to pnpm 10.33.4 via packageManager field
- add .npmrc with node-linker=hoisted for RN/Expo compatibility
- convert yarn resolutions to pnpm.overrides; pin psl@1.9.0 and @types/psl@1.1.1
  to keep types resolving under exports-aware resolution
- pin react-compiler-runtime and babel-plugin-react-compiler to real rc.3 (the
  deprecated "Wrong version name was published" tag would otherwise resolve)
- add pnpm.onlyBuiltDependencies allowlist for @sentry/cli, core-js-pure,
  esbuild, unrs-resolver
- regenerate pnpm-lock.yaml; delete yarn.lock; drop postinstall-postinstall
- update all workflows, Dockerfile, Dockerfile.embedr (root-level), Makefile,
  conductor.json; bskyembed/bskylink/bskyogcard/dev-env stay on yarn
- update docs (CLAUDE.md, docs/build.md, docs/testing.md, docs/localization.md,
  bskyweb/README.md, scripts/push-notification/README.md, BlueskyClip/README.md)

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

CLAUDE.md

@@ -22,25 +22,25 @@ Prefer using the latest features available for each of these libraries (exact ve
 
 ```bash
 # Development
-yarn start              # Start Expo dev server
-yarn web                # Start web version
-yarn android            # Run on Android
-yarn ios                # Run on iOS
+pnpm start              # Start Expo dev server
+pnpm web                # Start web version
+pnpm android            # Run on Android
+pnpm ios                # Run on iOS
 
 # Testing & Quality
-# IMPORTANT: Always use these yarn scripts, never call the underlying tools directly
-yarn test               # Run Jest tests
-yarn lint               # Run ESLint
-yarn typecheck          # Run TypeScript type checking
+# IMPORTANT: Always use these pnpm scripts, never call the underlying tools directly
+pnpm test               # Run Jest tests
+pnpm lint               # Run ESLint
+pnpm typecheck          # Run TypeScript type checking
 
 # Internationalization
 # DO NOT run these commands - extraction and compilation are handled by CI
-yarn intl:extract       # Extract translation strings (nightly CI job)
-yarn intl:compile       # Compile translations for runtime (nightly CI job)
+pnpm intl:extract       # Extract translation strings (nightly CI job)
+pnpm intl:compile       # Compile translations for runtime (nightly CI job)
 
 # Build
-yarn build-web          # Build web version
-yarn prebuild           # Generate native projects
+pnpm build-web          # Build web version
+pnpm prebuild           # Generate native projects
 ```
 
 ## Project Structure
@@ -503,8 +503,8 @@ function MyComponent() {
 
 ```bash
 # DO NOT run these commands - extraction and compilation are handled by a nightly CI job
-yarn intl:extract    # Extract new strings to locale files
-yarn intl:compile    # Compile translations for runtime
+pnpm intl:extract    # Extract new strings to locale files
+pnpm intl:compile    # Compile translations for runtime
 ```
 
 ## State Management