fix(compose): wait for the API to be healthy before starting nomos

nomos declared `depends_on: api: condition: service_started`, which only waits
for the container to exist. It came up while the API was still binding :8090,
failed its MCP initialize with "connection refused", exited 1, and crash-looped
for ~25 seconds on every single deploy. It always recovered on its own, which
is precisely why it went unnoticed.

service_healthy waits for the API to answer, so this needs api to declare a
healthcheck — wget is BusyBox's, already present in the alpine runtime image,
so nothing new is installed. /healthz pings the database, so "healthy" means
genuinely able to serve rather than merely listening.

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

docker-compose.yml

@@ -83,6 +83,18 @@ services:
     command: ["api"]
     stop_signal: SIGTERM
     stop_grace_period: 30s
+    # Exists so nomos can wait for the API to actually answer rather than just
+    # for its container to exist — see nomos's depends_on below. wget is
+    # BusyBox's, already in the alpine runtime image, so this adds no
+    # dependency. /healthz pings the DB, so "healthy" means genuinely ready.
+    healthcheck:
+      test: ["CMD", "wget", "-q", "-O", "-", "http://127.0.0.1:8090/healthz"]
+      interval: 5s
+      timeout: 3s
+      retries: 10
+      # Migrations and seed run before this container, but the first bind can
+      # still take a moment; failures inside the start period don't count.
+      start_period: 10s
 
   # Scheduler (Phase 3) — observe loop
   scheduler:
@@ -139,7 +151,12 @@ services:
     profiles: ["full"]
     depends_on:
       api:
-        condition: service_started
+        # service_started only waits for the container to exist, so nomos came
+        # up while the API was still binding :8090, failed its MCP initialize,
+        # exited 1, and crash-looped for ~25s on every single deploy. It always
+        # recovered, which is exactly why it went unnoticed. service_healthy
+        # waits for the API to actually answer.
+        condition: service_healthy
     environment:
       NOMOS_MCP_URL: http://api:8090/mcp
       NOMOS_AGENT_SLUG: agent:nomos