fix: accept no-op pushes where old_oid == new_oid

Fixes race condition where user's push becomes no-op after state event
is applied between fetch and push. Now accepts these as successful
no-ops, matching Git's 'Everything up-to-date' behavior.

- Add early detection in get_state_authorization_for_specific_owner_repo
- Return success for all-noop pushes without requiring purgatory event
- Document behavior in inline-authorization.md

docs/explanation/inline-authorization.md

@@ -352,6 +352,10 @@ pub async fn authorize_push(
    - If no event found, create placeholder (git-data-first scenario)
    - Collect PR events from purgatory for post-push processing
 
+**No-Op Push Acceptance:** Pushes where all refs have `old_oid == new_oid` are accepted without requiring a purgatory state event, matching Git's "Everything up-to-date" behavior and avoiding race condition rejections.
+
+---
+
 ## State Event Authorization
 
 State events (kind 30618) undergo authorization checks at three points (defense-in-depth):

src/git/authorization.rs

@@ -575,6 +575,28 @@ pub async fn get_state_authorization_for_specific_owner_repo(
         owner_pubkey
     );
 
+    // Accept pushes where all refs are already at the desired state (old_oid == new_oid)
+    // This handles race conditions where state events are applied between fetch and push
+    if !pushed_refs.is_empty() {
+        let all_refs_unchanged = pushed_refs
+            .iter()
+            .all(|(old_oid, new_oid, _)| old_oid == new_oid);
+
+        if all_refs_unchanged {
+            debug!(
+                "All pushed refs unchanged (old_oid == new_oid) for {} owned by {}, accepting without purgatory check",
+                identifier, owner_pubkey
+            );
+            return Ok(AuthorizationResult {
+                authorized: true,
+                reason: "Push accepted: all refs already at desired state (no-op)".to_string(),
+                state: None,
+                maintainers: authorized.into_iter().collect(),
+                purgatory_events: vec![],
+            });
+        }
+    }
+
     // Check purgatory for matching state events
     // Convert pushed refs to RefUpdate (filter out refs/nostr/* refs)
     let pushed_updates: Vec<RefUpdate> = pushed_refs