CI-9 follow-up: the skip direction, written the right way round

`every subsequent pull request matching it is skipped too` is the inverse of
the behaviour. A pull request that MATCHES a `branches:` filter still RUNS;
the one the filter EXCLUDES is what Gitea sits out, reports `skipped`, and the
rollup launders into `success`.

The error arrived with the generalisation in the previous commit: `33e17db`
said "every subsequent pull request is skipped too", which was unqualified and
true for the `[main]` case it described. Naming the wider hazard made a
qualifier necessary, and the wrong one went in - contradicting the paragraph
directly below it, which describes `[release/1.0]` correctly as leaving every
day-to-day PR running and green.

Corrected, and the direction is now stated explicitly with the failed draft
recorded, because this file already carries one instance of the same shape:
"That was wrong, it contradicted the checkout step's own note a few lines
below, and the error was not cosmetic."

Guard re-verified on the edited bytes: passes here, still refuses
`branches: [release/1.0]` added to the `on:` block. Comment-only, 0
non-comment lines changed.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01BwRLw7eKYj2byVdwB6kbjU

.gitea/workflows/checks.yml

@@ -116,8 +116,15 @@ name: checks
 # the guard lives inside the workflow that a filter makes Gitea skip. Blind
 # spot 3 is the one that matters: a filter naming a branch THIS pull request
 # does not target is itself skipped, lands green and untested, and then every
-# subsequent pull request matching it is skipped too. That is the gate off,
+# subsequent pull request the filter DOES NOT NAME is skipped too. That is the
-# silently.
+# gate off, silently.
+#
+# ⚠️ THAT DIRECTION IS THE WHOLE POINT AND IT IS EASY TO WRITE BACKWARDS. A
+# pull request that MATCHES the filter still runs; it is the one the filter
+# excludes that Gitea sits out, reports `skipped`, and the rollup launders
+# into `success`. An earlier draft of this very clause said "matching it is
+# skipped", which is the inverse of the measurement and contradicted the
+# paragraph directly below.
 #
 # ⚠️ AND THE DANGEROUS ONE IS NOT `branches: [main]`, WHICH AT LEAST LOOKS
 # WRONG. It is `branches: [release/1.0]`, which looks like tightening onto the