Phase 13: multi-host networks & images (0.14.0)

Networks and Images are now per-host, rendered as a section for the local host
plus one per registered agent (like the Stacks page).

- agent_app.py: new /agent/networks (list/inspect/containers/connect/disconnect/
  create/delete/prune) and /agent/images (list/updates/check), reusing
  network_service and a new image_service; DockerError mapped to HTTP status
  (forbidden -> 400 so the proxy doesn't treat it as a token failure).
- routers/agents.py: proxy routes at /api/agents/{id}/networks/* and
  /api/agents/{id}/images/*, audit-logging mutations.
- services/image_service.py: extracted the image-listing logic so the central
  router and the agent share it.
- Frontend: networksApi/imagesApi take an optional agentId; Networks/Images
  pages render NetworksSection/ImagesSection per host with a shared HostHeader.
  Remote "Prune unused" networks resolves the address-pool-exhaustion deploy
  error from the UI.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

backend/agent_app.py

@@ -36,11 +36,28 @@ from pydantic import BaseModel
 
 from config import settings
 from docker_client import DockerError, get_client, safe_call
-from services import backup_service, compose_service
+from services import (
+    backup_service,
+    compose_service,
+    image_service,
+    network_service,
+    update_service,
+)
 
 logger = logging.getLogger("stackpilot.agent")
 
-AGENT_VERSION = "0.13.2"
+# Map network_service's DockerError codes to HTTP status. forbidden is mapped to
+# 400 (not 403) so the central proxy doesn't misread it as a token failure.
+_DOCKER_STATUS = {"invalid_request": 400, "forbidden": 400, "not_found": 404}
+
+
+def _map_docker(exc: DockerError):
+    code = _DOCKER_STATUS.get(exc.error)
+    if code:
+        raise HTTPException(status_code=code, detail=exc.detail or exc.error)
+    raise exc  # falls through to the global 502 DockerError handler
+
+AGENT_VERSION = "0.14.0"
 
 
 # --------------------------------------------------------------------------- #
@@ -67,6 +84,21 @@ class StackBody(BaseModel):
     env: str | None = None
 
 
+class NetworkCreateBody(BaseModel):
+    name: str
+    driver: str = "bridge"
+    subnet: str | None = None
+    gateway: str | None = None
+    internal: bool = False
+    attachable: bool = True
+
+
+class ContainerRefBody(BaseModel):
+    container: str
+    aliases: list[str] | None = None
+    force: bool = False
+
+
 # --------------------------------------------------------------------------- #
 # Helpers
 # --------------------------------------------------------------------------- #
@@ -288,6 +320,92 @@ async def restore_stack(
             os.unlink(tmp.name)
 
 
+# --------------------------------------------------------------------------- #
+# Networks
+# --------------------------------------------------------------------------- #
+
+
+@app.get("/agent/networks", dependencies=[Depends(verify_token)])
+def list_networks() -> list[dict]:
+    return network_service.list_networks()
+
+
+@app.get("/agent/networks/{network_id}", dependencies=[Depends(verify_token)])
+def inspect_network(network_id: str) -> dict:
+    try:
+        return network_service.inspect_network(network_id)
+    except DockerError as exc:
+        _map_docker(exc)
+
+
+@app.get("/agent/networks/{network_id}/containers", dependencies=[Depends(verify_token)])
+def network_containers(network_id: str) -> list[dict]:
+    try:
+        return network_service.connectable_containers(network_id)
+    except DockerError as exc:
+        _map_docker(exc)
+
+
+@app.post("/agent/networks/{network_id}/connect", dependencies=[Depends(verify_token)])
+def connect_container(network_id: str, body: ContainerRefBody) -> dict:
+    try:
+        network_service.connect_container(network_id, body.container, body.aliases)
+    except DockerError as exc:
+        _map_docker(exc)
+    return {"ok": True}
+
+
+@app.post("/agent/networks/{network_id}/disconnect", dependencies=[Depends(verify_token)])
+def disconnect_container(network_id: str, body: ContainerRefBody) -> dict:
+    try:
+        network_service.disconnect_container(network_id, body.container, body.force)
+    except DockerError as exc:
+        _map_docker(exc)
+    return {"ok": True}
+
+
+@app.post("/agent/networks", dependencies=[Depends(verify_token)], status_code=201)
+def create_network(body: NetworkCreateBody) -> dict:
+    try:
+        return network_service.create_network(body.model_dump())
+    except DockerError as exc:
+        _map_docker(exc)
+
+
+@app.delete("/agent/networks/{network_id}", dependencies=[Depends(verify_token)])
+def delete_network(network_id: str) -> dict:
+    try:
+        network_service.delete_network(network_id)
+    except DockerError as exc:
+        _map_docker(exc)
+    return {"ok": True}
+
+
+@app.post("/agent/networks/prune", dependencies=[Depends(verify_token)])
+def prune_networks() -> dict:
+    return network_service.prune_networks()
+
+
+# --------------------------------------------------------------------------- #
+# Images
+# --------------------------------------------------------------------------- #
+
+
+@app.get("/agent/images", dependencies=[Depends(verify_token)])
+def list_images() -> list[dict]:
+    return image_service.list_images()
+
+
+@app.get("/agent/images/updates", dependencies=[Depends(verify_token)])
+def image_updates() -> dict:
+    return update_service.get_cache()
+
+
+@app.post("/agent/images/check", dependencies=[Depends(verify_token)])
+async def image_check() -> dict:
+    return await update_service.check_all()
+
+
 @app.websocket("/agent/ws/logs/{stack_id}")
 async def ws_logs(websocket: WebSocket, stack_id: str, token: str | None = Query(default=None)):
     """Stream `docker compose logs -f` to the central app (token via query param)."""