Rename the bridge to the forge service; this repository is the add-on

- bridge/ → forge/, module and binary ipcr-forge, image ghcr.io/yundera/ipcr-forge
  (was ipcr-forge-bridge); releases are plain vX.Y.Z tags (workflow image.yml)
- data folders $AppID/bridge/{state,secrets} → $AppID/forge/..., in-container /forge
- docs link to the engine (Yundera/ipcr) instead of relative paths; README

forge/state.go

@@ -19,7 +19,7 @@ const (
 	stFrozen  = "frozen"  // no longer public in Gitea (or deleted): no further sync, nothing retracted
 )
 
-// repoState is what the bridge remembers per Gitea repository, keyed by Gitea's numeric ID so a
+// repoState is what the forge service remembers per Gitea repository, keyed by Gitea's numeric ID so a
 // rename or a transfer keeps its Radicle ID.
 type repoState struct {
 	ID            int64     `json:"id"`