Add Gitea API release publishing to CLI helper

docs/PUBLISHING_APIS.md

@@ -1,4 +1,4 @@
-# Publishing Rivencraft with the Modrinth and CurseForge APIs
+# Publishing Rivencraft with the Gitea, Modrinth, and CurseForge APIs
 
 The local helper is [`scripts/publish_mod_sites.py`](../scripts/publish_mod_sites.py).
 It previews a release unless `--publish` is explicitly supplied. The current
@@ -8,6 +8,12 @@ is enabled for it.
 
 ## One-time token setup
 
+For Gitea, an existing personal access token is sufficient if it has
+`write:repository` scope. That scope covers release creation and attachment
+upload; do not grant `all` if a narrower token is available. Create or inspect
+tokens under [Gitea user settings → Applications](https://git.paddedcell.org/user/settings/applications).
+The helper checks token identity and scope without displaying the secret.
+
 Create a [Modrinth personal access token](https://docs.modrinth.com/api/#authentication)
 in account settings with `VERSION_CREATE` (upload) and `USER_READ` (read-only
 credential check) scopes. Create a
@@ -21,6 +27,7 @@ corresponding token into the hidden prompt:
 ```sh
 python3 scripts/publish_mod_sites.py store-token modrinth
 python3 scripts/publish_mod_sites.py store-token curseforge
+python3 scripts/publish_mod_sites.py store-token gitea
 ```
 
 The tokens are stored in the desktop Secret Service keyring under
@@ -34,6 +41,7 @@ Verify the credentials without uploading anything:
 ```sh
 python3 scripts/publish_mod_sites.py check-token modrinth
 python3 scripts/publish_mod_sites.py check-token curseforge
+python3 scripts/publish_mod_sites.py check-token gitea
 ```
 
 ## Release workflow
@@ -54,7 +62,18 @@ For a *new* version only, append `--publish` to upload to both sites. Use
 existing version number; CurseForge may not, so check its file list before any
 retry after a partial failure. CurseForge approval may take additional time.
 
-The helper uses Modrinth's documented multipart
+The default destination is now all three sites. The Gitea release step requires
+the annotated version tag to have been pushed first. Gitea's `Vx.y.z.b-mc26.3-beta.1`
+tag convention is derived from the version and channel; an existing release
+with different title or notes is never overwritten. If release creation
+succeeds but its JAR upload fails, rerun with `--site gitea --publish` to resume
+only the missing attachment. `--site both` retains the earlier Modrinth and
+CurseForge-only behavior.
+
+The helper uses Gitea's documented
+[`POST /repos/{owner}/{repo}/releases`](https://docs.gitea.com/api/operations/repo-create-release/)
+and [release attachment endpoint](https://docs.gitea.com/api/operations/repo-create-release-attachment/),
+plus Modrinth's documented multipart
 [`POST /version`](https://docs.modrinth.com/api/operations/createversion/) and
 CurseForge's documented
 [`POST /api/projects/{projectId}/upload-file`](https://support.curseforge.com/support/solutions/articles/9000197321)