feat(release): fold distribution back into the source repo

The separate J3vb/OwnCord-releases repo existed only because this repo was
private: it carried the AGPL source snapshot and provided a publicly-readable
update feed. Once this repo is public both roles collapse into its own Releases
page, so the mirror is pure redundancy.

- Server/config/config.go: github.repo default OwnCord-releases -> OwnCord.
  This one default drives both the server self-update and the client
  auto-update chain (tauri.conf.json updater.endpoints is empty, so the client
  resolves through the server). No test pinned the old value.
- release.yml: drop the mirror step and its RELEASES_REPO_TOKEN guard, whose
  AGPL/private-repo premise no longer holds. The existing Create GitHub Release
  step is now the sole publish target. All 31 SHA pins verified intact.
- Repoint the README badge/download link, both SECURITY.md links, the
  server-configuration table and sample, the system-overview diagram node and
  the CHANGELOG note. SECURITY.md's advisory link is the load-bearing one: left
  alone it would 404 once the mirror repo is deleted.
- README: Go 1.25+ -> 1.26+ (badge and prerequisite) to match the toolchain
  actually required.

Deleting the mirror repo loses nothing: both repos' v1.1.0-alpha.2 carry
byte-identical asset sets, signatures and update manifest included.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

docs/architecture/system-overview.md

@@ -31,7 +31,7 @@ flowchart LR
     end
 
     LK["LiveKit server<br/>(managed subprocess<br/>or external)"]
-    REL["OwnCord-releases<br/>(GitHub, minisign-signed)"]
+    REL["OwnCord releases<br/>(GitHub, minisign-signed)"]
 
     WV -->|"HTTPS REST<br/>⚠ accepts any cert<br/>(no pinning)"| RTR
     WSP -->|"WSS, fingerprint-pinned"| HUB

docs/server-configuration.md

@@ -74,7 +74,7 @@ For LiveKit options OwnCord does not model, you can take ownership of the auto-s
 |-----|------|---------|-------------|
 | `github.token` | string | `""` | Optional GitHub API token for higher rate limits on update checks (5000 req/hr vs 60) |
 | `github.owner` | string | `"J3vb"` | Owner of the GitHub repository server and client updates are fetched from |
-| `github.repo` | string | `"OwnCord-releases"` | Public releases repository. Must stay publicly readable — both the server self-update and the client auto-update chain fetch release assets from it |
+| `github.repo` | string | `"OwnCord"` | Repository whose releases carry update assets. Must stay publicly readable — both the server self-update and the client auto-update chain fetch release assets from it |
 
 ### Event Persistence (`event_persistence`)
 
@@ -208,7 +208,7 @@ voice:
 github:
   token: ""                        # optional GitHub PAT for update check rate limits
   owner: "J3vb"                    # update source repo owner
-  repo: "OwnCord-releases"         # public releases repo (binaries + source snapshots)
+  repo: "OwnCord"                  # repo holding release assets (binaries + source snapshots)
 
 # Event persistence (tiered reconnect replay)
 event_persistence: