fix: Use correct beads paths for molecule and statusline

- molecule.go: Use findLocalBeadsDir() for project-level beads
- statusline.go: Use findMailWorkDir() for mail count (town beads)

Part of two-level beads architecture cleanup.

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

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

internal/cmd/statusline.go

@@ -133,7 +133,7 @@ func runMayorStatusLine(t *tmux.Tmux) error {
 // Fast path - returns 0 on any error.
 func getUnreadMailCount(identity string) int {
 	// Find workspace
-	workDir, err := findBeadsWorkDir()
+	workDir, err := findMailWorkDir()
 	if err != nil {
 		return 0
 	}