Add flow settings, pulse emitting nodes, and simplify node state

- One dot per node now carries the whole story: primary while running, sage
  after a good run, red when anything is wrong, with the explanation on hover.
  The corner badge is gone, along with the second way of saying the same thing.
- A node that publishes something flashes a ring, so a running flow is legible
  without reading the edge values. Nodes that consume but publish nothing stay
  quiet, which is why the event carries an output count.
- Flow settings open in the same panel its nodes use, from a pencil in the
  dock: the title, the name, and deleting the flow. NodePanel and FlowPanel
  share the panel chrome rather than each drawing their own.
- Renaming is a server operation, because a flow's name is the namespace of its
  messages: the directory moves and every other flow reading `old.message` is
  repointed, instead of being left pointing at a flow that no longer exists.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016WzrvW7rjQbynnhF6pxh6i

frontend/src/client/schemas.gen.ts

@@ -586,6 +586,18 @@ export const PrivateUserCreateSchema = {
     title: 'PrivateUserCreate'
 } as const;
 
+export const RenameRequestSchema = {
+    properties: {
+        new_name: {
+            type: 'string',
+            title: 'New Name'
+        }
+    },
+    type: 'object',
+    required: ['new_name'],
+    title: 'RenameRequest'
+} as const;
+
 export const RunRequestSchema = {
     properties: {
         inputs: {