feat(primary): unify orchestrator status bar

[Amplify-Logic]

Summary

• Define one canonical Firstmate status-bar contract (docs/status-bar.md) with shared rendering in bin/fm-status-bar.sh and adapter-specific surfaces for Claude Code, Pi, and Kimi.
• Install only through guarded bin/fm-primary.sh launches (FM_PRIMARY_HARNESS); never mutates ~/.claude, ~/.kimi, ~/.pi, or ~/.cursor.
• Cursor CLI remains worker-only with no captain-facing primary or third-party status-line API; a captain-facing Cursor renderer is not applicable (documented in docs/status-bar.md and docs/cursor-harness.md).

Adapter surfaces

• Claude: tracked .claude/settings.json statusLine → bin/fm-status-bar.sh --adapter claude (absorbs the local prototype).
• Pi: tracked .pi/extensions/fm-primary-status-bar.ts via ctx.ui.setFooter() with width-safe truncation.
• Kimi: one-row tmux companion pane from the guarded kimi-k3 primary launch (no third-party footer API).
• Cursor: intentionally no installation; worker-only boundary preserved.

Local activation after merge

Remove the primary home's local .claude/settings.local.json statusLine override so tracked settings take effect. Do not copy renderers into state/ or edit operator-global homes.

Test plan

• bash tests/fm-status-bar.test.sh
• bash tests/fm-primary.test.sh (includes Kimi companion case)
• Live Claude / Pi / Kimi verification recorded in docs/status-bar.md
• After merge: remove local Claude statusLine override and confirm guarded primary launches show the bar