chore: migrate package manager from Yarn to Bun

- Remove Yarn-specific files (.yarnrc.yml, .yarn/, .pnp.cjs, .pnp.loader.mjs, yarn.lock)
- Add bun.lock for dependency locking
- Update package.json:
  - Change all scripts from 'yarn' to 'bun'
  - Update packageManager field to '[email protected]'
  - Convert 'resolutions' to 'overrides' (Bun/npm format)
  - Remove Yarn-specific 'dependenciesMeta'
- Update documentation:
  - README.md: Update installation command
  - AGENTS.md/CLAUDE.md: Update all development commands
  - CONTRIBUTING.md: Update setup and build instructions
  - Individual package READMEs: Update installation commands
- Update .gitignore to remove Yarn-specific entries
- Add workflows-bun-migration.patch for CI/CD workflow updates
  (to be applied separately with workflow permissions)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

Author: claude

.gitignore

@@ -1,15 +1,5 @@
-.yarn/*
-!.yarn/patches
-!.yarn/plugins
-!.yarn/releases
-!.yarn/sdks
-!.yarn/versions
-
-# Swap the comments on the following lines if you don't wish to use zero-installs
-# Documentation here: https://yarnpkg.com/features/zero-installs
-!.yarn/cache
+# Dependencies
 node_modules
-#.pnp.*
 
 /.idea/inspectionProfiles/Project_Default.xml
 /.idea/modules.xml