Summary

• Replace small internal patch and installation Zod schemas with Effect Schema while preserving JSON shape and schema metadata descriptions/identifier.
• Drop unused/internal Zod type imports from file watcher and provider schema transforms.
• Keep NamedError, plugin tool APIs, MCP SDK, and Copilot SDK internals untouched.

Verification

• bun run test -- test/patch/patch.test.ts test/tool/apply_patch.test.ts
• bun run test -- test/installation/installation.test.ts
• bun run test -- test/provider/transform.test.ts test/file/watcher.test.ts
• bun typecheck
• bunx prettier --check src/file/watcher.ts src/provider/transform.ts src/patch/index.ts src/installation/index.ts
• bunx oxlint packages/opencode/src/file/watcher.ts packages/opencode/src/provider/transform.ts packages/opencode/src/patch/index.ts packages/opencode/src/installation/index.ts