Merge branch 'main' into glitch-soc/merge-upstream

Conflicts:
- `.github/workflows/build-image.yml`:
  Upstream entirely refactored this, while we changed the docker repository
  to upload to and disabled the “latest” tag.
  Applied the repository change to `.github/workflows/build-*.yml`, as well
  as disabling native ARMv64 builds.
- `README.md`:
  We have a completely different README.
  Kept ours.
- `app/views/admin/settings/shared/_links.html.haml`:
  Upstream refactored, we had an extra item.
  Refactored as upstream did.
- `spec/controllers/api/v1/timelines/public_controller_spec.rb`:
  Upstream deleted this file, to be replaced by a request spec at
  `spec/requests/api/v1/timelines/public_spec.rb`.
  We had an extra bit about enabling the public timelines because we have
  different defaults than upstream.
  Moved that bit to `spec/requests/api/v1/timelines/public_spec.rb`

.github/workflows/build-releases.yml

@@ -0,0 +1,24 @@
+name: Build container release images
+on:
+  push:
+    tags:
+      - '*'
+
+permissions:
+  contents: read
+  packages: write
+
+jobs:
+  build-image:
+    uses: ./.github/workflows/build-container-image.yml
+    with:
+      platforms: linux/amd64,linux/arm64
+      use_native_arm64_builder: false
+      push_to_images: |
+        ghcr.io/${{ github.repository_owner }}/mastodon
+      flavor: |
+        latest=${{ startsWith(github.ref, 'refs/tags/v4.1.') }}
+      tags: |
+        type=pep440,pattern={{raw}}
+        type=pep440,pattern=v{{major}}.{{minor}}
+    secrets: inherit