fix: remove vestigial state.json files from agent directories

Agent directories (witness/, refinery/, mayor/) contained state.json files
with last_active timestamps that were never updated, making them stale and
misleading. This change removes:

- initAgentStates function that created vestigial state.json files
- AgentState type and related Load/Save functions from config package
- MayorStateValidCheck from doctor checks
- requesting_* lifecycle verification (dead code - flags were never set)
- FileStateJSON constant and MayorStatePath function

Kept intact:
- daemon/state.json (actively used for daemon runtime state)
- crew/<name>/state.json (operational CrewWorker metadata)
- Agent state tracking via beads (the ZFC-compliant approach)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

internal/rig/manager_test.go

@@ -40,7 +40,7 @@ func createTestRig(t *testing.T, root, name string) {
 		t.Fatalf("mkdir rig: %v", err)
 	}
 
-	// Create agent dirs
+	// Create agent dirs (witness, refinery, mayor)
 	for _, dir := range AgentDirs {
 		dirPath := filepath.Join(rigPath, dir)
 		if err := os.MkdirAll(dirPath, 0755); err != nil {
@@ -48,12 +48,6 @@ func createTestRig(t *testing.T, root, name string) {
 		}
 	}
 
-	// Create witness state.json (witnesses don't have clones, just state)
-	witnessState := filepath.Join(rigPath, "witness", "state.json")
-	if err := os.WriteFile(witnessState, []byte(`{"role":"witness"}`), 0644); err != nil {
-		t.Fatalf("write witness state: %v", err)
-	}
-
 	// Create some polecats
 	polecatsDir := filepath.Join(rigPath, "polecats")
 	for _, polecat := range []string{"Toast", "Cheedo"} {