Add CursorAgent CLI adapter

[ralfboltshauser]

Summary

• Add a native CursorAgent CLI adapter for cursor-agent stream JSON output.
• Register Cursor across the public agents and smithers facades, capability registry, CLI surface manifest, docs, and generated docs bundles.
• Add focused Cursor command-building/output-parsing tests and extend CLI capability coverage.
• Update Codex/CodexAgent-adjacent docs and eval fixtures to mention CursorAgent where Cursor is now an equivalent supported CLI worker.
• Add Cursor to smithers init agent scaffolding and local agent detection (cursor-agent status --format json or CURSOR_API_KEY).

Validation

• bun test --timeout=60000 --max-concurrency=1 packages/agents/tests/cursor-support.test.js packages/agents/tests/cli-capabilities.test.js
• Direct generateAgentsTs check for authenticated cursor-agent detection and CursorAgent scaffold output
• bun scripts/generate-llms.ts
• git diff --check

Known baseline/local-environment limitations

• ./node_modules/.bin/tsc -p packages/agents/tsconfig.json --noEmit fails on current main as well: packages/agents/src/SdkAgentOptions.ts(10,10): error TS2707: Generic type 'ToolLoopAgentSettings' requires between 0 and 3 type arguments.
• node scripts/check-docs.mjs still has unrelated baseline/environment failures: stale composite docs, optional package import resolution, missing VCS/time-travel deps, and CLI help checks blocked in this partial linked-dependency worktree; Cursor-related CLI agent docs checks pass.
• The full CLI init e2e suite was not rerun end-to-end because this isolated worktree does not have a complete workspace dependency install. incur is declared in the repo package manifests; Cursor detection/scaffold generation was validated directly instead.