Put the Route A driver in the repo and turn staging on for its release

.gitignore

@@ -14,6 +14,7 @@ out/
 
 # Release alert webhooks (real file is machine-local; .example is tracked)
 tools/release.env
+tools/route_a/route_a.env
 /inputs/
 
 # Finder metadata — never payload

changelog.d/route-a-driver-in-repo.added.md

@@ -0,0 +1 @@
+The Route A release driver now lives in `tools/route_a/` (driver, supervisor, sampler, static release-flag check, runbook) with every machine path in a git-ignored `route_a.env`; it previously existed only on the build machine. Its release stage stages telemetry by default: `with_hf_token.sh` fetches the Hugging Face token with `agent-secret` at exec time, so the token never reaches the stage config, argv or logs, and `ROUTE_A_STAGING=0` restores `--no-staging`. Every gate, the publisher's offline preflight and the `published: false` hand-off are unchanged; the published `4b57d15a2` release is unaffected.

docs/agent-guide.md

@@ -171,6 +171,13 @@ to the private repository; when you run `microcosm-build-uk`
 yourself, pass `--staging-local-only` unless the operator asked for a staged
 upload.
 
+The versioned Route A driver is `tools/route_a/route_a.sh`; see its
+[runbook](../tools/route_a/README.md) for configuration, preserved admission
+and release gates, and the Modal-base hand-off. Its release stage enables
+staging telemetry by default, obtains the HF credential only in a runtime
+wrapper, and accepts `ROUTE_A_STAGING=0` as the opt-out. It runs only the
+publisher's offline `--preflight-only` check and leaves publication to Max.
+
 The US fiscal-refresh builder scores its written H5 in household batches.
 Before a release rerun, run the small-H5 guard sweep described in
 [the release build rule](us-release-build-rule.md#post-export-scoring).