feat!: add cache service v2, add toolkit patches (#1110)

Serves `github.actions.results.api.v1.CacheService` next to the v1 cache API, sharing its store, plus the subset of the Azure blob protocol the toolkit uploads with. On by default via `cache.v2`, and works with `external_server`.

Clients reach it through two edits in the action's own bundle: the GHES check is opened, and the cache service URL is taken from `ACTIONS_CACHE_URL`.

The same GHES check is what makes the stock `actions/upload-artifact` and `download-artifact` abort on Gitea. Opening it makes them work without the `gitea-upload-artifact` fork, from `upload-artifact@v4.4.0` on.

Verified against 118 real bundles, every major version of 16 actions: 92 patched, the rest deliberately left alone, and every patched bundle checked with `node --check`. Also end to end against pinned `actions/cache@v6.1.0` with an unreachable results URL, so only the patch can make the cache work.

---------

Co-authored-by: silverwind <me@silverwind.io>
Co-authored-by: bircni <me@silverwind.io>
Reviewed-on: https://gitea.com/gitea/runner/pulls/1110
Reviewed-by: silverwind <2021+silverwind@noreply.gitea.com>

internal/pkg/config/config.example.yaml

@@ -155,6 +155,11 @@ cache:
   # A moved tag (e.g. a re-tagged "v6") or an updated branch stays at the cached commit
   # until its cache entry expires or is manually removed.
   offline_mode: false
+  # Serve the actions cache service v2 API, used by actions/cache@v4.2 and later. Those actions
+  # refuse any host they do not take for GitHub, so reaching it means editing that check out of
+  # the action's own bundle, keeping the untouched copy beside it. The same edit lets the stock
+  # upload-artifact and download-artifact work here. A bundle that does not match is left alone.
+  v2: true
 
 container:
   # Specifies the network to which the container will connect.