breakglass: in-cluster emergency-recovery UI for the devvm

Viktor wanted a web UI on the claude service to act as his breakglass when
the devvm is down: open it, have Claude SSH in to diagnose/repair, and
power-cycle the VM via the Proxmox host if needed. This is the app half
(the infra stack + host bootstrap live in the infra repo).

New, ISOLATED ASGI app under app/breakglass/ (never imports app.main, so the
untrusted-input agents — recruiter-triage, nextcloud-todos — can't share a
process with the root-on-devvm / PVE-reset SSH key):
- pve.py: the LLM-independent power-verb path (status|forensics|reset|stop|
  start|cycle on VM 102), whitelist-validated client-side, executed over the
  forced-command SSH key (list argv, no shell).
- agent_session.py: multi-turn streamed chat — claude -p --session-id /
  --resume with --output-format stream-json, translated to a small SSE
  vocabulary (session/text/tool/result/error/done).
- auth.py: edge Authentik header OR bearer; fail-closed.
- server.py: FastAPI (session/chat-SSE/pve-verb routes) + serves the Svelte UI.
- Svelte SPA (frontend/, built into app/breakglass/static/ and committed — no
  in-cluster build, per ADR-0002): streamed chat + danger-styled manual VM
  controls with confirm-on-mutate.
- agents/breakglass.md: narrow tools (Bash/Read/Grep/Glob, no web), taught the
  ssh devvm / ssh pve aliases and cycle-vs-reset.
- docker-entrypoint-breakglass.sh: ssh-agent bootstrap from the mounted key +
  ssh aliases, then uvicorn app.breakglass.server. The breakglass Deployment
  overrides the image CMD with this; the existing service is untouched.

26 new tests (verb whitelist incl. injection attempts, stream-json→SSE
translation, auth gating, route behaviour); full suite 58 green.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

app/breakglass/__init__.py

@@ -0,0 +1,10 @@
+"""Breakglass: an isolated emergency-recovery surface for the devvm.
+
+This package is a SEPARATE ASGI app from ``app.main``. The breakglass
+deployment runs ``uvicorn app.breakglass.server:app`` and mounts the SSH keys;
+the ordinary claude-agent-service deployment keeps running ``app.main:app`` and
+never sees those keys. Nothing here imports ``app.main`` and vice versa, so the
+untrusted-input agents (recruiter-triage, nextcloud-todos) can never share a
+process with the root-on-devvm / PVE-reset credentials. See
+``docs/adr/0001-breakglass-security-architecture.md``.
+"""