Add a custom Buf plugin that generates Zod schemas from proto definitions
with automatic validation rules from buf.validate annotations.

Features:
- Converts buf.validate constraints to Zod validations (.min(), .startsWith(), etc.)
- Generates enum helper maps (ENUM_MAP and STRING_TO_ENUM)
- Supports all scalar types, well-known types, and wrapper types
- Handles recursive message types with z.lazy()
- Skips empty files (no messages/enums)
- Uses z.enum() instead of deprecated z.nativeEnum() for Zod v4

New files:
- tools/zod/ - Custom protoc-gen-zod plugin source
- .npmrc - Buf registry config for @buf/* dependencies

fix: change module type from ESNext to CommonJS in package.json and tsconfig.gen.json

feat(validation): enhance item-level constraints for repeated fields in Zod schemas

feat(validation): add support for int64/uint64 constraints in Zod validation chains

feat(validation): update file_id validation to use pattern matching for file identifiers

feat(validation): enhance validation handling for optional fields and string patterns in Zod schemas

fix(filesystem): regex in fileFilter prefix

fix(filesystem): allow 'default' as valid context in UploadFileData

Update the context field validation pattern to accept 'default' as a valid
value in addition to the existing missions: and setups: prefixes.

chore: update devDependencies in package.json

- Bump @bufbuild/buf from 1.61.0 to 1.64.0
- Update @types/node from 25.0.3 to 25.2.0

fix(filesystem): enhance regex for prefix validation in FileFilter and UploadFileData

Updated the regex pattern for the 'prefix' field in FileFilter to prevent path traversal and ensure valid path formats. Additionally, added a pattern validation for the 'name' field in UploadFileData to enforce similar constraints.

fix(dependencies): update grpc-js, zod, and bufbuild packages to latest versions