fix: relocate daemon socket for deep paths (GH#1001)

On Unix systems, socket paths are limited to 104 chars (macOS) or 108 chars
(Linux). Deep workspace paths like /Volumes/External Drive/Dropbox/...
would exceed this limit and cause daemon startup failures.

This fix:
- Adds ShortSocketPath() which computes /tmp/beads-{hash}/bd.sock for
  paths that would exceed the limit
- Keeps backward compatibility: short paths still use .beads/bd.sock
- Updates daemon discovery to check both locations
- Uses SHA256 hash of canonical workspace path for unique directories

Closes GH#1001

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

internal/daemon/discovery.go

@@ -214,15 +214,28 @@ func FindDaemonByWorkspace(workspacePath string) (*DaemonInfo, error) {
 	// For worktrees, .beads is in the main repository root, not the worktree
 	beadsDir := findBeadsDirForWorkspace(workspacePath)
 
-	// First try the socket in the determined .beads directory
-	socketPath := filepath.Join(beadsDir, "bd.sock")
-	if _, err := os.Stat(socketPath); err == nil {
-		daemon := discoverDaemon(socketPath)
+	// Try short socket path first (GH#1001 - avoids macOS 104-char limit)
+	// This is computed from the workspace path, not the beads dir
+	mainWorkspace := filepath.Dir(beadsDir) // Get workspace from .beads dir
+	shortSocketPath := rpc.ShortSocketPath(mainWorkspace)
+	if _, err := os.Stat(shortSocketPath); err == nil {
+		daemon := discoverDaemon(shortSocketPath)
 		if daemon.Alive {
 			return &daemon, nil
 		}
 	}
 
+	// Try legacy socket path in .beads directory (backwards compatibility)
+	legacySocketPath := filepath.Join(beadsDir, "bd.sock")
+	if legacySocketPath != shortSocketPath {
+		if _, err := os.Stat(legacySocketPath); err == nil {
+			daemon := discoverDaemon(legacySocketPath)
+			if daemon.Alive {
+				return &daemon, nil
+			}
+		}
+	}
+
 	// Fall back to discovering all daemons
 	daemons, err := DiscoverDaemons([]string{workspacePath})
 	if err != nil {