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/constants/constants.go

@@ -64,9 +64,6 @@ const (
 	// FileTownJSON is the town configuration file in mayor/.
 	FileTownJSON = "town.json"
 
-	// FileStateJSON is the agent state file.
-	FileStateJSON = "state.json"
-
 	// FileConfigJSON is the general config file.
 	FileConfigJSON = "config.json"
 
@@ -176,11 +173,6 @@ func MayorTownPath(townRoot string) string {
 	return townRoot + "/" + DirMayor + "/" + FileTownJSON
 }
 
-// MayorStatePath returns the path to mayor state.json within a town root.
-func MayorStatePath(townRoot string) string {
-	return townRoot + "/" + DirMayor + "/" + FileStateJSON
-}
-
 // RigMayorPath returns the path to mayor/rig within a rig.
 func RigMayorPath(rigPath string) string {
 	return rigPath + "/" + DirMayor + "/" + DirRig