feat: changelog-driven versioning and idempotent Gitea registry release scripts

scripts/sync-upstream.ts

@@ -155,7 +155,12 @@ async function main() {
       upstream_version: upstreamPkg.version,
     }
     writeFileSync(path.join(SNAPSHOT_DIR, "UPSTREAM.json"), JSON.stringify(meta, null, 2) + "\n")
-    const state: UpstreamState = { ...meta, synced_at: new Date().toISOString() }
+    const state: UpstreamState & { previous_commit?: string | null; last_diff?: SnapshotDiff } = {
+      ...meta,
+      synced_at: new Date().toISOString(),
+      previous_commit: recorded?.commit ?? null,
+      last_diff: diff,
+    }
     writeFileSync(STATE_PATH, JSON.stringify(state, null, 2) + "\n")
 
     const fresh = recordNewSkills(CLASSIFICATION_PATH, diff.added)