feat(cursor): enable optimized auto worker dispatch

[mihaisavezi]

Summary

• accept Cursor's balanced, cost, and intelligence parameterized auto models when the live catalog exposes plain auto
• preserve live-catalog rejection for unknown model ids
• document Auto Balance as the standing default and require explicit named overrides for Cost or Intelligence

Test plan

• bash tests/fm-spawn-dispatch-profile.test.sh
• bin/fm-lint.sh bin/fm-cursor-lib.sh tests/fm-spawn-dispatch-profile.test.sh
• bin/fm-doc-audience-check.sh
• git diff --check

Notes

• The full no-argument lint reached the workflow check but could not run it because actionlint 1.7.12 is not installed; no workflow files changed.