refactor: rename egress-proxy → egress everywhere

The manifest key is `egress:` now; finish the rename so the rest of
the codebase matches. Files (Dockerfile.egress, claude_bottle/egress.py
etc.), classes (Egress, EgressConfig, EgressRoute, EgressPlan,
DockerEgress), constants (EGRESS_HOSTNAME, EGRESS_ROUTES, ...),
container name prefix (claude-bottle-egress-*), docker network alias
(egress), the introspection host (_egress.local), the MCP tool IDs
(egress-block, list-egress-routes), and the preflight label all drop
the `-proxy` suffix.

claude_bottle/backend/__init__.py

@@ -231,7 +231,7 @@ class BottleBackend(ABC, Generic[PlanT, CleanupT]):
 
     def provision_ca(self, plan: PlanT, target: str) -> None:
         """Install the per-bottle CA into the agent's trust store so
-        the agent trusts the bumped CONNECT cert egress-proxy (was
+        the agent trusts the bumped CONNECT cert egress (was
         pipelock, pre-PRD-0017) presents. Default impl is a no-op so
         backends that don't yet support TLS interception (every backend
         except Docker today) aren't forced to implement it. The Docker