feat(provision): install pipelock CA into the agent + add curl

Second step of PRD 0006. With pipelock now doing the bumping, the
agent's TLS library has to trust pipelock's per-bottle CA — or
every CONNECT to api.anthropic.com is a self-signed-cert error.

- BottleBackend.provision gains a non-abstract `provision_ca`
  with a default no-op (so non-Docker backends aren't forced to
  implement TLS interception) and orchestrates
  ca → prompt → skills → ssh → git. CA install runs first so the
  agent's trust store is rebuilt before anything else in the
  agent makes a TLS call.

- New backend/docker/provision/ca.py: docker-cp's the CA cert
  into the agent at /usr/local/share/ca-certificates/...,
  `update-ca-certificates`, then emits a one-line stderr log
  with the SHA-256 fingerprint (stdlib `ssl` + `hashlib`; no
  subprocess for crypto). Module-level constants AGENT_CA_PATH
  and AGENT_CA_BUNDLE are imported by launch.py so the env
  trio set at docker run time matches the paths the provisioner
  writes.

- launch.py: rebinds `plan` after `dataclasses.replace`s on the
  pipelock proxy plan so provision_ca (which reads
  `plan.proxy_plan.ca_cert_host_path`) sees the populated CA
  paths. Three new -e flags on the agent's docker run for the
  NODE_EXTRA_CA_CERTS / SSL_CERT_FILE / REQUESTS_CA_BUNDLE trio.

- Dockerfile: adds curl to the apt-get install line. curl
  natively respects HTTPS_PROXY and sends CONNECT directly —
  the agent doesn't need OS-level DNS for external hostnames
  (pipelock resolves them on its side of the bumped tunnel).
  This is the "simple HTTPS request" path the earlier turn
  needed and Node's stdlib https.request couldn't provide.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

claude_bottle/backend/docker/backend.py

@@ -24,6 +24,7 @@ from .bottle import DockerBottle
 from .bottle_cleanup_plan import DockerBottleCleanupPlan
 from .bottle_plan import DockerBottlePlan
 from .pipelock import DockerPipelockProxy
+from .provision import ca as _ca
 from .provision import git as _git
 from .provision import prompt as _prompt
 from .provision import skills as _skills
@@ -47,6 +48,9 @@ class DockerBottleBackend(BottleBackend["DockerBottlePlan", "DockerBottleCleanup
         with _launch.launch(plan, proxy=self._proxy, provision=self.provision) as bottle:
             yield bottle
 
+    def provision_ca(self, plan: DockerBottlePlan, target: str) -> None:
+        _ca.provision_ca(plan, target)
+
     def provision_prompt(self, plan: DockerBottlePlan, target: str) -> str | None:
         return _prompt.provision_prompt(plan, target)