docs: fix stale references to grasp-02-proactive-sync-v4.md

The design doc lives at docs/explanation/grasp-02-proactive-sync.md; the
-v4 filename referenced from the sync module headers and architecture doc
never existed in the tree. Reference-only change.

docs/explanation/architecture.md

@@ -558,7 +558,7 @@ The ngit-grasp relay implements **Proactive Sync of Nostr Events**, which synchr
 
 **Source Code:** [`src/sync/`](../../src/sync/)
 
-For full design details, see [grasp-02-proactive-sync-v4.md](grasp-02-proactive-sync-v4.md).
+For full design details, see [grasp-02-proactive-sync.md](grasp-02-proactive-sync.md).
 
 ### Rejected Events Index
 
@@ -697,6 +697,6 @@ ngit-grasp uses inline authorization at the HTTP handler level, giving full cont
 ## Related Documentation
 
 - [Inline Authorization Explanation](inline-authorization.md) - Why we chose this approach
-- [GRASP-02 Proactive Sync v4 Design](grasp-02-proactive-sync-v4.md) - Current production sync implementation
+- [GRASP-02 Proactive Sync Design](grasp-02-proactive-sync.md) - Current production sync implementation
 - [Test Strategy](../reference/test-strategy.md) - Comprehensive testing documentation
 - [GRASP-01 Implementation Learnings](../learnings/grasp-01-implementation.md) - Patterns and lessons learned

src/sync/algorithms.rs

@@ -5,7 +5,7 @@
 //! - `derive_relay_targets()` - Inverts RepoSyncIndex to per-relay view
 //! - `compute_actions()` - Three-way diff to determine new sync actions
 //!
-//! See `docs/explanation/grasp-02-proactive-sync-v4.md` for full design details.
+//! See `docs/explanation/grasp-02-proactive-sync.md` for full design details.
 
 use std::collections::{HashMap, HashSet};
 

src/sync/filters.rs

@@ -7,7 +7,7 @@
 //! - Layer 2: Events tagging our repos (a/A/q tags)
 //! - Layer 3: Events tagging our root events (e/E/q tags)
 //!
-//! See `docs/explanation/grasp-02-proactive-sync-v4.md` for full design details.
+//! See `docs/explanation/grasp-02-proactive-sync.md` for full design details.
 
 use std::collections::HashSet;
 

src/sync/mod.rs

@@ -10,7 +10,7 @@
 //! - `RelaySyncIndex` - What we have CONFIRMED syncing + connection state
 //! - `PendingSyncIndex` - In-flight batches awaiting EOSE confirmation
 //!
-//! See `docs/explanation/grasp-02-proactive-sync-v4.md` for full design details.
+//! See `docs/explanation/grasp-02-proactive-sync.md` for full design details.
 
 pub mod algorithms;
 pub mod filters;

src/sync/self_subscriber.rs

@@ -6,7 +6,7 @@
 //! This module subscribes to relevant event kinds on our own relay and
 //! batches updates before sending them to the SyncManager.
 //!
-//! See `docs/explanation/grasp-02-proactive-sync-v4.md` for full design details.
+//! See `docs/explanation/grasp-02-proactive-sync.md` for full design details.
 
 use std::collections::{HashMap, HashSet};
 use std::time::Duration;