fix(plugins): close the 4 PARTIAL findings + regressions from the fix-verify pass

A second adversarial pass over the first remediation found four findings only
partially closed and five issues the fixes themselves introduced. This closes
them:

Partial → closed
- re-consent gate keyed on `granted.length > 0`, so a plugin first activated with
  ZERO permissions (granted '[]') was treated as never-consented and a later
  widening was granted silently. Now discovery marks a never-consented plugin with
  granted_permissions '' and activate() gates on "ever consented" (any non-empty
  string, including '[]').
- db:own DoS: block WITH RECURSIVE outright (the one construct that spins the
  synchronous host unboundedly regardless of the size/row caps, via query OR exec).
- dgram: also wrap `new dgram.Socket(...)` (bypassed createSocket) to inject the
  IP-vetting lookup, and lock createSocket/Socket.
- frame self-navigation: documented as a bounded best-effort mitigation (inherent
  to sandboxed iframes; exposure is the plugin's own routes + already-held context,
  never the httpOnly cookie).

Regressions introduced by the first pass → fixed
- proxy: only real redirects (301/302/303/307/308) are gated, to a RELATIVE in-app
  Location (supports OAuth-callback bounce, blocks open redirect); 300/304 pass
  through; attachment only on non-redirects.
- supervisor: measure RSS via /proc/<pid>/status VmRSS (page-size independent);
  activation-timeout awaits kill() before disposing the db handle.
- manifest HOST_RE: allow single-label hosts (self-hoster sibling services) while
  keeping wildcards multi-label; mirrored in the SDK + frame CSP filter.

Regression tests added (re-consent incl. the '[]' case, WITH RECURSIVE + row cap,
single-label host). 236 plugin tests + 24 SDK tests green.

server/src/nest/plugins/plugin-frame.controller.ts

@@ -72,7 +72,7 @@ export class PluginFrameController {
     // (a stray space or `*` would inject an extra CSP source token).
     const outbound = this.runtime
       .outboundHostsOf(pluginId)
-      .filter((h) => /^(\*\.)?[a-z0-9-]+(\.[a-z0-9-]+)+$/i.test(h));
+      .filter((h) => /^(\*\.[a-z0-9-]+(\.[a-z0-9-]+)+|[a-z0-9-]+(\.[a-z0-9-]+)*)$/i.test(h));
     const connect = ["'self'", ...outbound.map((h) => `https://${h}`)].join(' ');
     return [
       "default-src 'none'",