refactor: remove Gas Town references from codebase

Replace Gas Town-specific terminology with generic orchestrator concepts:
- "Gas Town" → "orchestrator" or "multi-clone"
- Hardcoded ~/gt/ paths → GT_ROOT environment variable
- signalGasTownActivity → signalOrchestratorActivity
- GUPP → hook-based work assignment

Updated 21 files across CHANGELOG, cmd/bd/, internal/, docs/, scripts.

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

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

Executed-By: beads/crew/dave
Rig: beads
Role: crew

internal/beads/beads.go

@@ -603,7 +603,7 @@ func findDatabaseInTree() string {
 // FindAllDatabases scans the directory hierarchy for the closest .beads directory.
 // Returns a slice with at most one DatabaseInfo - the closest database to CWD.
 // Stops searching upward as soon as a .beads directory is found,
-// because in multi-workspace setups (like Gas Town), nested .beads directories
+// because in multi-workspace setups, nested .beads directories
 // are intentional and separate - parent directories are out of scope.
 // Redirect files are supported: if a .beads/redirect file exists, its contents
 // are used as the actual .beads directory path.

internal/beads/beads_multidb_test.go

@@ -64,7 +64,7 @@ func TestFindAllDatabases(t *testing.T) {
 	databases := FindAllDatabases()
 
 	// Should find only the closest database (gt-bzd: stop searching when .beads found)
-	// Parent .beads directories are out of scope in multi-workspace setups like Gas Town
+	// Parent .beads directories are out of scope in multi-workspace setups
 	if len(databases) != 1 {
 		t.Fatalf("expected 1 database (closest only), got %d", len(databases))
 	}

internal/formula/parser.go

@@ -39,7 +39,7 @@ type Parser struct {
 
 // NewParser creates a new formula parser.
 // searchPaths are directories to search for formulas when resolving extends.
-// Default paths are: .beads/formulas, ~/.beads/formulas, ~/gt/.beads/formulas
+// Default paths are: .beads/formulas, ~/.beads/formulas, $GT_ROOT/.beads/formulas
 func NewParser(searchPaths ...string) *Parser {
 	paths := searchPaths
 	if len(paths) == 0 {
@@ -65,9 +65,11 @@ func defaultSearchPaths() []string {
 	// User-level formulas
 	if home, err := os.UserHomeDir(); err == nil {
 		paths = append(paths, filepath.Join(home, ".beads", "formulas"))
+	}
 
-		// Gas Town formulas
-		paths = append(paths, filepath.Join(home, "gt", ".beads", "formulas"))
+	// Orchestrator formulas (via GT_ROOT)
+	if gtRoot := os.Getenv("GT_ROOT"); gtRoot != "" {
+		paths = append(paths, filepath.Join(gtRoot, ".beads", "formulas"))
 	}
 
 	return paths

internal/molecules/molecules.go

@@ -8,7 +8,7 @@
 //
 // Molecules are loaded from multiple locations in priority order (later overrides earlier):
 //  1. Built-in molecules (shipped with bd binary)
-//  2. Town-level: ~/gt/.beads/molecules.jsonl (if Gas Town is detected)
+//  2. Town-level: $GT_ROOT/.beads/molecules.jsonl (if orchestrator detected via GT_ROOT)
 //  3. User-level: ~/.beads/molecules.jsonl
 //  4. Project-level: .beads/molecules.jsonl in the current project
 //
@@ -77,7 +77,7 @@ func (l *Loader) LoadAll(ctx context.Context, beadsDir string) (*LoadResult, err
 		}
 	}
 
-	// 2. Load town-level molecules (Gas Town: ~/gt/.beads/molecules.jsonl)
+	// 2. Load town-level molecules ($GT_ROOT/.beads/molecules.jsonl)
 	townPath := getTownMoleculesPath()
 	if townPath != "" {
 		if molecules, err := loadMoleculesFromFile(townPath); err == nil && len(molecules) > 0 {
@@ -220,15 +220,15 @@ func loadMoleculesFromFile(path string) ([]*types.Issue, error) {
 }
 
 // getTownMoleculesPath returns the path to town-level molecules.jsonl
-// if Gas Town is detected (~/gt/.beads/molecules.jsonl).
+// if an orchestrator is detected via GT_ROOT environment variable.
 func getTownMoleculesPath() string {
-	homeDir, err := os.UserHomeDir()
-	if err != nil {
+	gtRoot := os.Getenv("GT_ROOT")
+	if gtRoot == "" {
 		return ""
 	}
 
-	// Check for Gas Town installation
-	gtPath := filepath.Join(homeDir, "gt", ".beads", MoleculeFileName)
+	// Check for orchestrator molecules file
+	gtPath := filepath.Join(gtRoot, ".beads", MoleculeFileName)
 	if _, err := os.Stat(gtPath); err == nil {
 		return gtPath
 	}

internal/routing/routes.go

@@ -221,7 +221,7 @@ func ResolveToExternalRef(id, beadsDir string) string {
 
 // ResolveBeadsDirForID determines which beads directory contains the given issue ID.
 // It first checks the local beads directory, then consults routes.jsonl for prefix-based routing.
-// If routes.jsonl is not found locally, it searches up to the Gas Town root.
+// If routes.jsonl is not found locally, it searches up to the town root.
 //
 // Parameters:
 //   - ctx: context for database operations
@@ -273,7 +273,7 @@ func ResolveBeadsDirForID(ctx context.Context, id, currentBeadsDir string) (stri
 	return currentBeadsDir, false, nil
 }
 
-// findTownRoot walks up from startDir looking for a Gas Town root.
+// findTownRoot walks up from startDir looking for a town root.
 // Returns the town root path, or empty string if not found.
 // A town root is identified by the presence of mayor/town.json.
 func findTownRoot(startDir string) string {
@@ -294,7 +294,7 @@ func findTownRoot(startDir string) string {
 // findTownRoutes searches for routes.jsonl at the town level.
 // It walks up from currentBeadsDir to find the town root, then loads routes
 // from <townRoot>/.beads/routes.jsonl.
-// Returns (routes, townRoot). Returns nil routes if not in a Gas Town or no routes found.
+// Returns (routes, townRoot). Returns nil routes if not in an orchestrator town or no routes found.
 func findTownRoutes(currentBeadsDir string) ([]Route, string) {
 	// First try the current beads dir (works if we're already at town level)
 	routes, err := LoadRoutes(currentBeadsDir)
@@ -306,7 +306,7 @@ func findTownRoutes(currentBeadsDir string) ([]Route, string) {
 	// Walk up to find town root
 	townRoot := findTownRoot(currentBeadsDir)
 	if townRoot == "" {
-		return nil, "" // Not in a Gas Town
+		return nil, "" // Not in a town
 	}
 
 	// Load routes from town beads