Plugin: self-hosted auto-updates from Gitea via PUC (hc-8gb)

Vendors YahnisElsts/plugin-update-checker v5.7 under vendor/ and wires it
to poll updates.json on the repo main branch. WP surfaces new versions
via Dashboard → Updates on its normal twice-daily cadence.

PUC is vendored (not a submodule) so Gitea's archive/main.zip — the
download target — includes it. Folder rename on install is handled by
PUC's built-in upgrader_source_selection filter.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

vendor/plugin-update-checker/.gitattributes

@@ -0,0 +1,6 @@
+/.editorconfig export-ignore
+/.gitattributes export-ignore
+/.gitignore export-ignore
+/build/ export-ignore
+/examples/ export-ignore
+/phpcs.xml export-ignore