fix(herdr): B5 — replace invented pane.kill/release/rotation_signal with real methods

Verified against a live herdr instance (192.168.1.105:9245) that pane.kill,
pane.release, and pane.rotation_signal never existed in the protocol, as
AUDIT.md's B5 suspected. Real method list captured in deploy/herdr-schema.json.

- Kill now calls the real pane.close({pane_id}).
- RotationSignal interface/method/call-site deleted; no real equivalent exists.
- Release now refuses loudly instead of calling a nonexistent method — the
  real pane.release_agent can't return a handoff_ref either way (herdr
  doesn't write handoffs, the agent does), so a real fix needs Phase 4
  handoff production first.

Also documents Phase 0 findings in AUDIT.md/progress.md, and adds
CLAUDE.md/AGENTS.md with project-specific knowledge (herdr protocol facts,
deployment topology, a currently-stuck live task, the federation fork) for
future sessions.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01W1rkJ2hBMybnJctPbcy4tT

internal/orchestrator/orchestrator.go

@@ -451,13 +451,8 @@ func (c *Coordinator) rotate(ctx context.Context, hard float64) {
 			continue
 		}
 		reason := "threshold"
-		if signal, ok := a.(herdr.RotationSignal); ok {
-			if r, signalErr := signal.RotationSignal(ctx, session); signalErr == nil && r != "" {
-				reason = r
-			}
-		}
 		occupancy, err := a.Occupancy(session)
-		if err != nil || (occupancy < hard && reason == "threshold") {
+		if err != nil || occupancy < hard {
 			continue
 		}
 		// Face B is treated as required, not best-effort (spec §5.2/§5.3):