feat(dashboard): Add Polecat Workers section with activity monitoring

- Add FetchPolecats() to fetch tmux session data for active polecats
- Display polecat name, rig, activity status (green/yellow/red)
- Show status hint from last line of pane output
- Add FetchMergeQueue stub for interface compliance
- Update handler to pass polecats data to template
- Add Polecat Workers table section to convoy.html

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

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

internal/web/handler.go

@@ -8,6 +8,8 @@ import (
 // ConvoyFetcher defines the interface for fetching convoy data.
 type ConvoyFetcher interface {
 	FetchConvoys() ([]ConvoyRow, error)
+	FetchMergeQueue() ([]MergeQueueRow, error)
+	FetchPolecats() ([]PolecatRow, error)
 }
 
 // ConvoyHandler handles HTTP requests for the convoy dashboard.
@@ -37,8 +39,22 @@ func (h *ConvoyHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
+	mergeQueue, err := h.fetcher.FetchMergeQueue()
+	if err != nil {
+		// Non-fatal: show convoys even if merge queue fails
+		mergeQueue = nil
+	}
+
+	polecats, err := h.fetcher.FetchPolecats()
+	if err != nil {
+		// Non-fatal: show convoys even if polecats fail
+		polecats = nil
+	}
+
 	data := ConvoyData{
-		Convoys: convoys,
+		Convoys:    convoys,
+		MergeQueue: mergeQueue,
+		Polecats:   polecats,
 	}
 
 	w.Header().Set("Content-Type", "text/html; charset=utf-8")