Remove redundant ID Zod overrides

[kitlangton]

Summary

• Remove redundant ZodOverride annotations from prefixed ID schemas now that Effect schemas carry the same prefix checks.
• Move the remaining ToolID / EventID prefix constraints to Effect schemas too.
• Remove the now-unused Identifier.schema(...) helper and unused identifier prefix entries.
• Keep ID constructors and .zod statics backed by Effect schema-derived Zod output.

Testing

• bun test --timeout 5000 test/server/httpapi-query-schema-drift.test.ts test/cli/github-action.test.ts test/project/migrate-global.test.ts test/session/message-v2.test.ts
• bun typecheck
• bunx prettier --check packages/opencode/src/id/id.ts packages/opencode/src/tool/schema.ts packages/opencode/src/sync/schema.ts packages/opencode/src/control-plane/schema.ts packages/opencode/src/permission/schema.ts packages/opencode/src/pty/schema.ts packages/opencode/src/question/schema.ts packages/opencode/src/session/schema.ts
• bunx oxlint packages/opencode/src/id/id.ts packages/opencode/src/tool/schema.ts packages/opencode/src/sync/schema.ts packages/opencode/src/control-plane/schema.ts packages/opencode/src/permission/schema.ts packages/opencode/src/pty/schema.ts packages/opencode/src/question/schema.ts packages/opencode/src/session/schema.ts
• pre-push bun turbo typecheck

Stack

• Source HTTP API ID path patterns #26623
• Source workspace path pattern #26632
• Remove redundant ID Zod overrides #26633 ← current