Give the panel the canvas, and open a flow already fitted

Opening a node or the flow settings now takes the flowbar and the dock
away, leaving the graph and the panel; they come back on close, leaving
by the same slideUp they arrive with. The panel header names the flow
before the node, `/heating/`, which is how messages are qualified
everywhere else.

Opening a flow already fitted, and pressing Fit to screen, disagreed:
one used a 0.25 padding capped at 1x, the other xyflow's defaults, so
the button visibly jumped and a small flow opened at 100% in an empty
canvas. Both read one constant now.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01KkmeRiyeYmVZqJVwuyHq9o

frontend/src/components/Flow/NodePanel.tsx

@@ -459,14 +459,21 @@ export function NodePanel({
       onClose={onClose}
       header={
         node ? (
-          <Input
-            value={node.title || node.id}
-            aria-label="Node name"
-            className="h-8 flex-1 text-sm font-medium"
-            onChange={(event) =>
-              onChange({ ...node, title: event.target.value })
-            }
-          />
+          <div className="flex min-w-0 flex-1 items-center gap-1.5">
+            {/* Where the node lives: the flow is the namespace of its
+                messages, so it reads like the folder holding them. */}
+            <span className="min-w-0 truncate font-mono text-sm text-muted-foreground">
+              /{flow}/
+            </span>
+            <Input
+              value={node.title || node.id}
+              aria-label="Node name"
+              className="h-8 flex-1 text-sm font-medium"
+              onChange={(event) =>
+                onChange({ ...node, title: event.target.value })
+              }
+            />
+          </div>
         ) : null
       }
       footer={