ci: run the gate on branch pushes only, not on release tags

A release pushes main and then the v<ver> tag, and a bare `on: [push]` treated
the tag as a second push of the identical commit — every release ran the whole
gate twice to the same verdict (runs #81-#90 are five such pairs).

It has to be `branches`, not the `tags-ignore` this obviously wants to be:
Gitea's matchPushEvent requires every named filter to match and each one bails
on the wrong ref kind, so `tags-ignore` rejects every BRANCH push and silently
disables the gate. Measured in go-gitea v1.27.3, where it differs from GitHub.

A trigger filter that stops firing is invisible, so the ops `release` now reads
the verdict back for the sha it pushed and says so when there is no run for it.

.gitea/workflows/check.yml

@@ -15,7 +15,25 @@
 # `frontend/src/lib/nodeEngine.contract.test.ts` fails this gate if any of them drift apart.
 name: gate
 
-on: [push, pull_request]
+# Branch pushes only. A release pushes `main` and then the `v<ver>` tag, and a bare `on: [push]`
+# treated the tag as a second push of the IDENTICAL commit — every release ran this whole gate
+# twice, to the same verdict, for nothing (runs #81-#90 are five such pairs). `branches: ['**']`
+# keeps every branch covered and drops tag refs.
+#
+# It has to be `branches`, NOT the `tags-ignore` this obviously wants to be. Gitea's matchPushEvent
+# requires EVERY named filter to match, and each one bails on the wrong ref kind: `tags-ignore`
+# starts with `if !refName.IsTag() { break }`, so a filter meant to skip tags rejects every BRANCH
+# push and the gate stops running entirely. `branches` bails the same way on a tag, which is the
+# direction we want. (Measured in go-gitea v1.27.3 modules/actions/workflows.go, not assumed — it
+# differs from GitHub, where `tags-ignore` alone leaves branches unfiltered.)
+#
+# If that filter were ever wrong the gate would not run at all — which is why `siftlode release`
+# now ends by reading the verdict back for the sha it pushed, and says so out loud when there is
+# no run for it. A gate that silently stops running is the failure this repo already lived through.
+on:
+  push:
+    branches: ["**"]
+  pull_request:
 
 jobs:
   frontend: