archetypes: build an archetype agent from its archetype's module on the hive

The hive reads the agent-archetype key when it provisions and rebuilds an
agent and keeps it in swarm-agent-archetypes.json. For an archetype agent
the meta flake has no agent-<name> input and mkAgent imports
hyperhive.hyperhiveArchetypes.<name>.module; provisioning, rebuilds, the
meta-input cascade, a deploy's rev and the startup migration skip the
config repos. The harness gets HIVE_ARCHETYPE and the system prompt says
the agent has no config repo. The create form sends the picked archetype.
Adds the android-dev built-in.

Refs #5386

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

@@ -61,3 +61,13 @@ export function prefill(
     },
   };
 }
+
+/**
+ * The `archetype` field of `POST /api/agents` for `archetype`, or nothing for
+ * a custom agent.
+ */
+export function requestArchetype(
+  archetype: Archetype | undefined,
+): { source: string; name: string } | undefined {
+  return archetype && { source: archetype.source, name: archetype.name };
+}

frontend/packages/swarm-ui/src/pages/CreateAgentForm.tsx

@@ -57,6 +57,7 @@ import {
 import {
   archetypeKey,
   prefill,
+  requestArchetype,
   type ArchetypeList,
 } from "./CreateAgentArchetype.js";
 import "./CreateAgentForm.css";
@@ -230,6 +231,7 @@ export function CreateAgentForm({
           permissions: catalogue
             ? requestPermissions(selected, catalogue.default)
             : undefined,
+          archetype: requestArchetype(picked),
         }),
       });
       if (!r.ok) {
@@ -321,7 +323,9 @@ export function CreateAgentForm({
                 />
                 {picked && (
                   <p class="create-agent-archetype-description">
-                    {picked.description}
+                    {picked.description} An agent created from an archetype has
+                    no config repo: its hive builds it from the archetype's
+                    module.
                   </p>
                 )}
               </>
@@ -396,7 +400,9 @@ export function CreateAgentForm({
             Submitting this queues everything a new agent needs: a swarm-level
             identity, a config repo on the forge with the operator added as a
             collaborator, and a container running the agent on the hive you pick
-            above. Watch it all settle on <Link href="/jobs">jobs</Link>.
+            above. An agent created from an archetype gets no config repo: its
+            container runs the archetype's module. Watch it all settle on{" "}
+            <Link href="/jobs">jobs</Link>.
           </p>
         </Panel>
       </div>