refactor(swarm): one file per endpoint, matching existing router layout

Splits the three grouped router files into eight api_<verb>_<resource>.py
modules under decnet/web/router/swarm/ to match the convention used by
router/fleet/ and router/config/. Shared request/response models live in
_schemas.py. Keeps each endpoint easy to locate and modify without
stepping on siblings.

decnet/web/router/swarm/api_deploy_swarm.py

@@ -0,0 +1,104 @@
+"""POST /swarm/deploy — shard a DecnetConfig across enrolled workers.
+
+Per worker we build a filtered copy containing only the deckies assigned
+to that worker (via ``host_uuid``), then POST it to the worker agent.
+The caller is expected to have already set ``host_uuid`` on every decky;
+if any decky arrives without one, we fail fast. Auto-sharding lives in
+the CLI layer, not here.
+"""
+from __future__ import annotations
+
+import asyncio
+import json
+from datetime import datetime, timezone
+from typing import Any
+
+from fastapi import APIRouter, Depends, HTTPException
+
+from decnet.config import DecnetConfig, DeckyConfig
+from decnet.logging import get_logger
+from decnet.swarm.client import AgentClient
+from decnet.web.db.repository import BaseRepository
+from decnet.web.dependencies import get_repo
+from decnet.web.router.swarm._schemas import (
+    DeployRequest,
+    DeployResponse,
+    HostResult,
+)
+
+log = get_logger("swarm.deploy")
+
+router = APIRouter()
+
+
+def _shard_by_host(config: DecnetConfig) -> dict[str, list[DeckyConfig]]:
+    buckets: dict[str, list[DeckyConfig]] = {}
+    for d in config.deckies:
+        if not d.host_uuid:
+            raise HTTPException(
+                status_code=400,
+                detail=f"decky '{d.name}' has no host_uuid — caller must shard before dispatch",
+            )
+        buckets.setdefault(d.host_uuid, []).append(d)
+    return buckets
+
+
+def _worker_config(base: DecnetConfig, shard: list[DeckyConfig]) -> DecnetConfig:
+    return base.model_copy(update={"deckies": shard})
+
+
+@router.post("/deploy", response_model=DeployResponse, tags=["Swarm Deployments"])
+async def api_deploy_swarm(
+    req: DeployRequest,
+    repo: BaseRepository = Depends(get_repo),
+) -> DeployResponse:
+    if req.config.mode != "swarm":
+        raise HTTPException(status_code=400, detail="mode must be 'swarm'")
+
+    buckets = _shard_by_host(req.config)
+
+    hosts: dict[str, dict[str, Any]] = {}
+    for host_uuid in buckets:
+        row = await repo.get_swarm_host_by_uuid(host_uuid)
+        if row is None:
+            raise HTTPException(status_code=404, detail=f"unknown host_uuid: {host_uuid}")
+        hosts[host_uuid] = row
+
+    async def _dispatch(host_uuid: str, shard: list[DeckyConfig]) -> HostResult:
+        host = hosts[host_uuid]
+        cfg = _worker_config(req.config, shard)
+        try:
+            async with AgentClient(host=host) as agent:
+                body = await agent.deploy(cfg, dry_run=req.dry_run, no_cache=req.no_cache)
+            for d in shard:
+                await repo.upsert_decky_shard(
+                    {
+                        "decky_name": d.name,
+                        "host_uuid": host_uuid,
+                        "services": json.dumps(d.services),
+                        "state": "running" if not req.dry_run else "pending",
+                        "last_error": None,
+                        "updated_at": datetime.now(timezone.utc),
+                    }
+                )
+            await repo.update_swarm_host(host_uuid, {"status": "active"})
+            return HostResult(host_uuid=host_uuid, host_name=host["name"], ok=True, detail=body)
+        except Exception as exc:
+            log.exception("swarm.deploy dispatch failed host=%s", host["name"])
+            for d in shard:
+                await repo.upsert_decky_shard(
+                    {
+                        "decky_name": d.name,
+                        "host_uuid": host_uuid,
+                        "services": json.dumps(d.services),
+                        "state": "failed",
+                        "last_error": str(exc)[:512],
+                        "updated_at": datetime.now(timezone.utc),
+                    }
+                )
+            return HostResult(host_uuid=host_uuid, host_name=host["name"], ok=False, detail=str(exc))
+
+    results = await asyncio.gather(
+        *(_dispatch(uuid_, shard) for uuid_, shard in buckets.items())
+    )
+    return DeployResponse(results=list(results))