fix(mq): gt mq list shows all priorities, not just P0 (gt-72so)

The ListOptions struct defaults Priority to 0 (Go zero value), which
caused bd list to filter to only P0 merge requests. This fix explicitly
sets Priority: -1 to disable priority filtering.

Root cause: beads.ListOptions{Type: "merge-request"} created opts with
Priority=0, passing --priority=0 to bd, filtering out P1-P4 MRs.

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

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

internal/cmd/mq.go

@@ -543,8 +543,10 @@ func runMQList(cmd *cobra.Command, args []string) error {
 	b := beads.New(r.Path)
 
 	// Build list options - query for merge-request type
+	// Priority -1 means no priority filter (otherwise 0 would filter to P0 only)
 	opts := beads.ListOptions{
-		Type: "merge-request",
+		Type:     "merge-request",
+		Priority: -1,
 	}
 
 	// Apply status filter if specified