Add Owner and PublicName fields to TownConfig (gt-6r18e.3)

Adds federation identity fields to town.json:
- Owner: email address for entity identity (defaults to git user.email)
- PublicName: public display name (defaults to town name)

Schema version bumped to 2. Existing town.json files remain compatible
as new fields are optional.

Also adds --owner and --public-name flags to 'gt install'.

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

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

internal/config/types.go

@@ -8,10 +8,12 @@ import (
 
 // TownConfig represents the main town identity (mayor/town.json).
 type TownConfig struct {
-	Type      string    `json:"type"`    // "town"
-	Version   int       `json:"version"` // schema version
-	Name      string    `json:"name"`    // town identifier
-	CreatedAt time.Time `json:"created_at"`
+	Type       string    `json:"type"`                  // "town"
+	Version    int       `json:"version"`               // schema version
+	Name       string    `json:"name"`                  // town identifier (internal)
+	Owner      string    `json:"owner,omitempty"`       // owner email (entity identity)
+	PublicName string    `json:"public_name,omitempty"` // public display name
+	CreatedAt  time.Time `json:"created_at"`
 }
 
 // MayorConfig represents town-level behavioral configuration (mayor/config.json).
@@ -70,7 +72,8 @@ type AgentState struct {
 }
 
 // CurrentTownVersion is the current schema version for TownConfig.
-const CurrentTownVersion = 1
+// Version 2: Added Owner and PublicName fields for federation identity.
+const CurrentTownVersion = 2
 
 // CurrentRigsVersion is the current schema version for RigsConfig.
 const CurrentRigsVersion = 1