ci(core-ref): pin to the Teams cutover, not a phase 3 edge sha

The pin said "edge @ Teams phase 3" and edge is about to stop existing. More to
the point, this module has since gained the Team provider, three declared slots,
the /guild command and the contribution names on those slots - none of which the
pinned core knew about, so the frozen-manifest job has been proving this module
against a core older than half of it.

routes.manifest.json does not move: the job compares core-with-module against
core-without-module, so core's own Teams routes cancel out and what is left is
this module's 73, unchanged. Verified locally against the cutover core before
moving the pin rather than after.

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

ci/core-ref.json

@@ -1,6 +1,6 @@
 {
   "$comment": "The core this module is proved against. MODULE_API.md §5.3: the frozen-manifest job clones RunicGateway/website at this exact ref, drops this module in as modules/uo and runs CORE's own routeManifest.js — nothing else can answer whether the URLs the module claims are the URLs it actually serves. Pinned rather than tracking `edge` on purpose: core moves for reasons that have nothing to do with this module, and a bump is then a deliberate commit saying which core the module was last proved against, instead of an unexplained red X on someone else's PR. Bump it, regenerate routes.manifest.json, and commit both together.",
   "repo": "https://gitea.whitlocktech.com/RunicGateway/website.git",
-  "ref": "7ed2ac99838f4bd64e1df324fe4961673648b0e6",
-  "refName": "edge @ Teams phase 3 (website#152)"
+  "ref": "963d734dcc09580a7d8bb676370b4faf9b8727b2",
+  "refName": "main @ the Teams cutover (website#161)"
 }