fix(security): template integration sovereign audit + critical fixes

P0 — three critical issues found by tracing every attack vector on the template
publish + fork + render path. All three fixed and verified with attack tests.

FIX A — Takedown actually stops malicious containers
  PATCH /v1/admin/templates with status=takedown previously only updated
  mcp_servers.status to 'paused' in the DB. The Docker container kept running
  and serving traffic on its allocated port — takedown was cosmetic. Now the
  endpoint enumerates every fork's container, calls 'docker rm -f' on each,
  clears container_id/public_url/host_port in the DB, and returns the
  stoppedContainers count. New apps/api/src/lib/docker.ts owns the stop logic.
  Verified: takedown stopped container f5632962, port 4109 connection refused.

FIX B — Reject specEdit on fork
  A hand-crafted POST /v1/servers with {templateId, previewId, specEdit} would
  enter the spec-edit branch, merge edits into the cached spec, but the worker
  reads the pre-built template code (separate cache key), ignoring the merged
  spec entirely. User thinks they changed something; deployed container behaves
  as the original. Now returns 400 spec_edit_forbidden_on_fork with an explainer
  pointing to the Iterate flow.

FIX C — templateId validation via Redis fork-ref
  templateId on POST /v1/servers was user-controlled and unvalidated:
  fork_count of any template could be pumped, mcp_servers got garbage
  template_id rows, takedown cascade would miss the bogus rows. Fork endpoint
  now writes a Redis key fork-ref:<previewId> -> templateId (5min TTL).
  Server-create requires the ref to exist AND match the submitted templateId.
  Verified attack: fake templateId without fork-ref returns 410 fork_ref_expired.

DEFENSE-IN-DEPTH — Hardened static checks

  Banned patterns (added):
    Function\s*\(['"`]    — Function('code')() form, no 'new' needed
    \bimport\s*\(           — dynamic import escapes bundle scope
    \bsetTimeout\s*\(['"`] — setTimeout('code', ms) eval form
    \bsetInterval\s*\(['"`]
    \bfs\s*\.\s*(unlink|rmdir|rm)\b
    \bprocess\s*\.\s*kill\b
    you are now in (developer|jailbreak|dan) mode — extra jailbreak markers

  Hardcoded-credential patterns (new — scanForLeakedSecrets):
    sk-ant-(api|sid)…  — Anthropic
    sk-…               — OpenAI
    sk_(live|test)_…   — Stripe
    ghp_…              — GitHub PAT
    github_pat_…       — GitHub fine-grained
    xox[bpoasr]-…      — Slack
    AKIA[0-9A-Z]{16}   — AWS
    -----BEGIN…PRIVATE KEY----- — RSA / SSH / GPG
  Triggered when a publisher pasted their key into the prompt and Claude
  embedded it literally in the generated code. Publish-blocking.
  Verified attack: smuggled 'Function("return 1")' into a build's
  generated_code, attempted publish → 422 publish_blocked.

  Slug regex tightened — fork + detail routes now require
  ^[a-z0-9][a-z0-9-]{0,63}$ (was loose min(1).max(64) — letting through
  '../admin', long strings, mixed case).

  UI warning — Publish-as-template form now shows an amber callout listing
  what's scanned and explicitly stating egress allowlisting is roadmap, not
  enforced today (was misleading: the field was collected, never enforced).

  TEMPLATE_SECURITY_AUDIT.md added — documents all 20 audited vectors with
  severity, status, and rationale for what's deferred.

UI polish
  globals.css — select/input/textarea/button get color-scheme: dark + custom
  chevron + option styling so Chrome's native popdown stops rendering as a
  white OS-themed widget on dark pages. The /templates category dropdown was
  the immediate trigger; same rule applies system-wide.

apps/web/app/globals.css

@@ -46,6 +46,28 @@
     outline: 2px solid var(--color-accent);
     outline-offset: 2px;
   }
+  /* Force dark native UI for form controls — Chrome popdown otherwise reverts to OS light theme */
+  select,
+  input,
+  textarea,
+  button {
+    color-scheme: dark;
+  }
+  /* Style native select arrow + ensure the dropdown popdown uses our dark token */
+  select {
+    background-image: url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 24 24' fill='none' stroke='%23a1a1aa' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'><polyline points='6 9 12 15 18 9'/></svg>");
+    background-repeat: no-repeat;
+    background-position: right 8px center;
+    background-size: 12px;
+    -webkit-appearance: none;
+    -moz-appearance: none;
+    appearance: none;
+    padding-right: 26px !important;
+  }
+  select option {
+    background: var(--color-bg-elevated);
+    color: var(--color-fg);
+  }
   /* Scrollbars */
   ::-webkit-scrollbar {
     width: 10px;