fix(server): gate cost/log endpoints against cross-site requests and ship a full CSP

The cost-bearing endpoints (/api/realtime/token, /api/openai/hud-summary,
/api/google/nearby-places) and the voice debug log refuse cross-site browser
requests: a foreign or opaque Origin, a Sec-Fetch-Site other than
same-origin/none, or proxy forwarding headers. Loopback tools without an
Origin and the LAN opt-in keep working. The dev and preview servers send one
shared Content-Security-Policy, and embed-mode framing rewrites only the
frame-ancestors directive of it.

Salvaged from #242 onto current main.

Co-authored-by: Sameh Khamis <[email protected]>
Co-Authored-By: Claude Opus 5.5 (1M context) <[email protected]>

scripts/format-scope.json

@@ -76,6 +76,7 @@
   "server/providers/places/routes.js",
   "src/data/placeProviderPayloads.js",
   "src/tooling/placeProviders.test.mjs",
+  "server/providers/common/same-site.js",
   "server/providers/space.js",
   "server/providers/space/celestrak.js",
   "server/providers/space/launch-library.js",