docs: renumber PRD 0081 -> 0083 across the reconcile chunk

Follows the base PR's renumber (0081 was already taken; main is on 0082). Update
every `PRD 0081` reference in the gateway-attach code, tests, and ADR 0006, plus
ADR 0006's link to the PRD file. No behaviour change.

Refs #516, #519.

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

bot_bottle/backend/macos_container/infra_launch.py

@@ -99,7 +99,7 @@ def ensure_gateway(
 
 def running_agent_containers() -> list[str]:
     """Every running agent container's name — the bottles the bring-up reconcile
-    attaches to the fresh gateway (PRD 0081). Raises `EnumerationError` if the
+    attaches to the fresh gateway (PRD 0083). Raises `EnumerationError` if the
     live set can't be determined (fail hard rather than reconcile a partial
     set)."""
     return [f"{CONTAINER_NAME_PREFIX}{agent.slug}" for agent in enumerate_active()]
@@ -108,7 +108,7 @@ def running_agent_containers() -> list[str]:
 def push_ca_to_container(name: str, ca_pem: str) -> None:
     """(Re)attach one running agent container to the current gateway: replace
     its trusted gateway CA with `ca_pem` and rebuild its trust store via
-    `container cp` + `container exec` (PRD 0081). Unconditional install — there
+    `container cp` + `container exec` (PRD 0083). Unconditional install — there
     is one gateway, so no fingerprint match is needed.
 
     Fail hard: raises `InfraLaunchError` (naming the container) on any failure —