agent permissions: one set, tool groups included, set at agent creation

mara on #5170: "dont split caps and perms. its all perms. / dont include
the now empty tool groups / nothing set -> default / also add perms to
agent creation screen".

- hive-sh4re: one `Permission` enum (messaging, meta, inbox, execution,
  web_tools, manage_root_agent) replaces `ToolGroup` and `Capability`;
  `lifecycle`/`forge` are gone. `Permission::default_for` is the default
  for an agent the swarm sets nothing for.
- The record is `{ "permissions": [...] }`. Missing key, unset field or
  no successful read yet = default; `[]` = none; a failed read after a
  good one keeps the last value.
- hive-agent reads its own key every 10s and builds each turn's --tools,
  --allowedTools and MCP config (rewritten before every turn) from it;
  the subagent daemon reads it on each start/continue. Agents get a
  read-only grant on their own key.
- hive-c0re restarts an agent only when its manage_root_agent changes.
  The import now merges meta/capabilities.json and meta/tool-groups.json
  into one list per agent and deletes both; the "import pending, don't
  read" decision is `ImportOutcome::read_allowed`, table-tested.
- swarm-controller: `GET /api/permissions` (names + default) and an
  optional `permissions` on `POST /api/agents`, stored before the job is
  queued. swarm-ui's create-agent form gets a permissions field.
- Deleted: HIVE_TOOL_GROUPS and its forward to the subagent daemon,
  tool_groups.rs, ruth's tool-group seed, the permissions rebuild job
  (PermPayload/WritePermFile/perm_change), the dashboard permissions tab
  and its stale-entries panel.

Part of #5170.

frontend/packages/swarm-ui/src/pages/CreateAgentPermissions.ts

@@ -0,0 +1,24 @@
+// The create-agent form's permissions logic, kept out of the component so
+// `npm test` can run it.
+
+/** `selected` with `value` added, or removed when it is there. */
+export function togglePermission(selected: string[], value: string): string[] {
+  return selected.includes(value)
+    ? selected.filter((p) => p !== value)
+    : [...selected, value];
+}
+
+/**
+ * The `permissions` to send with a create: `undefined` while `selected` is
+ * the default set (in any order), so the agent's key stays unset and follows
+ * the default; otherwise the list, which may be empty.
+ */
+export function requestPermissions(
+  selected: string[],
+  defaults: string[],
+): string[] | undefined {
+  const same =
+    selected.length === defaults.length &&
+    selected.every((p) => defaults.includes(p));
+  return same ? undefined : selected;
+}