Event-driven world time sync (timeSync flag)

Introduce an optional timeSync field and event-driven time pushes so host time is only re-applied on connect, resume-from-freeze, or large jumps while weather continues on ~1 Hz heartbeats. Added IsGameTimeFrozen detection and client buffering of latest host time; clients apply host time only when timeSync is true or when gameplay just resumed. Updated networking to read/write timeSync, adjusted F4TWorldStateSync logic (separate time vs weather send/apply paths, changed function signatures and behavior), and updated protocol/docs/changelog and fake_client logging to reflect the new field and behavior.

docs/architecture.md

@@ -30,9 +30,11 @@ both send and receive paths:
 11. The server tracks a world-state host (`worldStateHostPlayerId`). The first
     connected client becomes host; when the host disconnects, the server reassigns
     host to the lowest remaining `playerId` and broadcasts `worldStateHost`. The
-    host sends low-frequency `worldState` packets with `gameHour`, `gameDaysPassed`,
-    and optional `weatherFormId`. Promoted hosts continue with their already-synced
-    local time and weather so remaining clients should not see a jump.
+    host sends `worldState` packets with `gameHour`, `gameDaysPassed`, optional
+    `weatherFormId`, and optional `timeSync`. Weather heartbeats run at ~1 Hz;
+    time is pushed with `timeSync: true` on connect, after time freezes (menus,
+    loads, saves), and on large time jumps. Promoted hosts continue with their
+    already-synced local time and weather so remaining clients should not see a jump.
 12. On the game-thread update path, the proxy controller reads a copied
     remote-player snapshot before attempting any actor work. The snapshot is
     sorted by `playerId`, and only remote players with valid transform data in

docs/dev-log.md

@@ -9,6 +9,42 @@ failed experiments, successful tests, and next steps.
 
 ---
 
+## 2026-06-23 - Event-Driven Time Sync
+
+### Summary
+Improved host-authoritative time sync so calendar time stays aligned without constant heartbeat updates. The host (client 1) now pushes time with `timeSync: true` after gameplay time resumes from freezes (menus, pip-boy, dialogue, loading screens, save/load, wait/sleep). Non-host clients buffer the latest host time during freezes and snap on resume.
+
+### Files Changed
+- `plugin/include/F4TWorldStateSync.h`
+- `plugin/src/F4TWorldStateSync.cpp`
+- `plugin/include/F4TNetworking.h`
+- `plugin/src/F4TNetworking.cpp`
+- `protocol/world-state.md`
+- `changelog.md`
+- `server/fake_client.py`
+
+### Details
+- Added `IsGameTimeFrozen()` detection using `Main` flags, open menus, save/load busy state, and sleeping.
+- Split host send logic: weather continues on ~1 Hz heartbeat; time sends on initial connect, resume-from-freeze, or large time jumps.
+- Added optional `timeSync` field on `worldState` packets so weather-only heartbeats do not re-apply time on clients.
+- Clients store latest host time from every packet and force-apply when local gameplay time resumes.
+
+### Testing
+- Not run in-game in this session.
+- Recommended manual checks:
+  - Connect host first, then second client; verify times match after load.
+  - Open pip-boy on client 2 while host keeps playing; close pip-boy and confirm client 2 snaps to host time (`Applied host world time` in log).
+  - Wait/sleep on host; confirm `timeSync=yes` in host log and clients update.
+  - Verify weather still updates on ~1 Hz outdoors without constant time apply logs.
+
+### Known Issues
+- None currently known.
+
+### Next Steps
+- In-game two-instance verification across load screens and pause menu exits.
+
+---
+
 ## 2026-06-22 - World-State Host Reassignment
 
 ### Summary

docs/protocol-phase2-extensions.md

@@ -105,6 +105,7 @@ Full field definitions live in [`protocol/world-state.md`](../protocol/world-sta
   "gameHour": 14.25,
   "gameDaysPassed": 12.5,
   "weatherFormId": "00123456",
+  "timeSync": true,
   "clientTime": 1717424000.123,
   "serverTime": 1717424000.456
 }