fix(compose): RW mount + restart policy for agents-N overlays (B1 follow-up)

[zzylol]

Summary

ASAPCollector#389 (skip no-op RemoteConfig + advertise ReportsRemoteConfig)
and ASAPCollector#391 (add remote_config_path to stock asap-otel-agent-* OpAMP
blocks) made the patched opampextension persist controller-pushed RemoteConfig
to /etc/otel/config.yaml and exit, expecting Docker to restart the container so
the new config takes effect.

The stock single-node agents-N{1,10,100}.yml overlays were mounting that path
read-only and had no restart policy. So on a real OpAMP apply against a
stock deploy the agent would EROFS on the disk write and stay down — defeating
the whole #391 wiring.

This PR mirrors the working contract already used by the smoke harness overlay
(/mydata/mvp-smoke-test/compose/smoke-overlay.yml):

• drop :ro from the /etc/otel/config.yaml mount in each overlay's x-agent anchor
• add restart: unless-stopped to the same anchor

Both edits are required — RW alone leaves the agent dead after exit; restart alone leaves the on-disk write failing.

Files touched

• deploy/mvp-singlenode/docker-compose/gen-agents.sh — generator template (source of truth for N10/N100)
• deploy/mvp-singlenode/docker-compose/agents-N10.yml — regenerated via ./gen-agents.sh 10
• deploy/mvp-singlenode/docker-compose/agents-N100.yml — regenerated via ./gen-agents.sh 100
• deploy/mvp-singlenode/docker-compose/agents-N1.yml — hand-maintained sibling (its layout diverges from the generator), edited directly

Test plan

• python3 -c "import yaml; [yaml.safe_load(open(f)) for f in [...]]" parses all three overlays
• grep -c "restart:" agents-N*.yml non-zero on all three
• No :ro remains on the /etc/otel/config.yaml mount line in any of the three
• docker compose -f base.yml -f agents-N1.yml config resolves; agent mount has no read_only: true and restart: unless-stopped is materialized per agent
• CI green

Reference: smoke-overlay at /mydata/mvp-smoke-test/compose/smoke-overlay.yml
established this contract — the stock overlays now match.

Generated with Claude Code