fix(ci): stop telling readers the runner can't run upload-artifact@v4+

build.yml and baseline.yml both explained a missing artifact step by
saying act_runner cannot run actions/upload-artifact@v4+ (and baseline.yml
said ci-requirements.md records that, which it does not). The runner is
now gitea/runner 3.x, which edits the action's GHES refusal out of its
bundle, and stock v4+ is proven working on this forge (Scribe spike #3843).

Comments only. Neither lane gains an upload step: build-web still reads
the signed XPI from the release asset, and the baseline candidate is
still printed to the log, because those remain the better channels. The
comments now say why for the right reason.

Scribe snippet #2271, milestone 395.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01DwoKYuw3qJmUUYsJeNherB

.forgejo/workflows/build.yml

@@ -445,11 +445,12 @@ jobs:
           trap - EXIT
           echo "Uploaded fabledcurator-$VERSION.xpi to ext-$VERSION release"
 
-      # No actions/upload-artifact step: Forgejo Actions (and our
-       # act_runner) doesn't support upload-artifact@v4+ (GHES limitation
-       # surfaced 2026-05-26). Instead build-web reads the signed XPI
-       # straight from the ext-<version> Forgejo release we just uploaded
-       # to. Same source of truth; no double-store.
+      # No actions/upload-artifact step: build-web reads the signed XPI
+      # straight from the ext-<version> Forgejo release we just uploaded to.
+      # Same source of truth; no double-store. The step was dropped 2026-05-26
+      # because act_runner could not run upload-artifact@v4+; gitea/runner 3.x
+      # can (Scribe snippet #2271), but the release asset stays the better
+      # channel for a file build-web needs on every run.
 
   build-web:
     # Consumed by smoke-web's job-level `if:`. It cannot read `env` — the env