fix(supervise): reach the queue over RPC, get bot-bottle.db off the data plane

PRD 0070's rule — only the orchestrator opens bot-bottle.db; the data
plane reaches state through the control-plane RPC — was not in force.
Three data-plane daemons held a direct read-write handle on the shared
SQLite file: the supervise MCP server, the egress DLP addon (the most
attack-exposed process, TLS-bumping hostile traffic), and the git-gate
pre-receive hook. An RCE in any of them could read every bottle's
plaintext identity_token and forge attribution fleet-wide (issue #469).

Add the agent half of the supervise flow to the control plane:

  POST /supervise/propose  -> queue a proposal, 201 {proposal_id}
  POST /supervise/poll     -> non-blocking decision poll, 200 {status,...}

Both attribute the caller by (source_ip, identity_token) exactly like
/resolve — never a caller-supplied slug — so a bottle can only ever queue
or read its own proposals even if the data plane is compromised. A decided
poll archives server-side, preserving the archive-after-read contract.

Data plane: the supervise server, egress addon, and git-gate hook now
queue/poll through PolicyResolver.propose_supervise / poll_supervise
instead of opening the DB. supervise_server keeps its ~30s grace window
by polling the RPC; egress keeps its safelist keyed by resolved bottle;
the git-gate hook gets (source_ip, identity_token) from the CGI env.

Packaging: drop the DB bind-mount and SUPERVISE_DB_PATH from the
data-plane containers/VMs (docker gateway + infra, macOS infra,
firecracker infra). The orchestrator remains the sole opener of the one
file via BOT_BOTTLE_ROOT / host_db_path().

Update PRD 0070: the rule is now in force; remove the transitional caveat.

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

Dockerfile.gateway

@@ -26,8 +26,9 @@
 #   /git-gate-entrypoint.sh              docker-cp'd at start time
 #   /git-gate/creds/*                    docker-cp'd at start time
 #   /git/*                               bare repos, populated at runtime
-#   /run/supervise/bot-bottle.db         bind-mounted at run time
 #   /home/mitmproxy/.mitmproxy/          mitmproxy CA dir
+# (No bot-bottle.db mount: the data plane reaches the supervise queue over the
+#  control-plane RPC and never opens the DB — PRD 0070 / issue #469.)
 #
 # Exposed ports inside the container:
 #   9099  egress (mitmproxy, agent-facing HTTPS proxy)