feat(backend): reconcile running bottles' CA on gateway bring-up (0081)

Add `attach_bottled_agents_to_gateway()` as an `@abc.abstractmethod` on
`BottleBackend` and implement the first reconcile step across all three
backends: on a gateway cold boot, replace every already-running agent's
trusted CA with the freshly-minted gateway CA. Reconciling running bottles
is a backend responsibility (only the backend can enumerate its agents and
reach them — firecracker over SSH, docker/macOS over exec/cp), so making it
an abstract method keeps the fix cross-backend by construction.

The gateway rootfs is ephemeral, so a rebuild mints a new CA that every
running bottle distrusts (SSL verification fails — #510). This reconcile is
what distributes the fresh CA, so a routine gateway rebuild now doubles as a
free CA rotation. Per-bottle steps are best-effort: one unreachable or
malformed bottle is logged and skipped, never blocking the others.

Trigger — `Gateway.connect_to_orchestrator` now returns a cold-boot bool
(True when it actually (re)brought the gateway up, False when a healthy
current gateway was left untouched); each infra `ensure_running` gates the
reconcile on it, so it fires exactly on cold boot and never on an adopt.

Git-gate re-provision and egress-token restore fold into this same reconcile
on the same trigger in follow-up PRs (#516).

Refs #516. Addresses #510.

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

bot_bottle/backend/firecracker/infra.py

@@ -67,9 +67,17 @@ class FirecrackerInfraService(InfraService):
             # holds the signing key) mints the role-scoped `gateway` JWT for the
             # gateway, which never sees the key (#469).
             orchestrator.ensure_running(startup_timeout=startup_timeout)
-            self.gateway().connect_to_orchestrator(
+            cold_booted = self.gateway().connect_to_orchestrator(
                 orchestrator.gateway_url(), orchestrator.mint_gateway_token())
             infra_vm.record_booted_version(want)
+            # The fresh gateway rootfs minted a new CA and lost every bottle's
+            # git-gate/token state; reconcile the already-running bottles against
+            # it so a gateway rebuild doesn't silently break their egress
+            # (PRD 0081). Cold-boot only — the adopt fast-paths above never reach
+            # here, so a healthy current gateway is left untouched.
+            if cold_booted:
+                from .backend import FirecrackerBottleBackend
+                FirecrackerBottleBackend().attach_bottled_agents_to_gateway()
             return url
 
     def stop(self) -> None: