T6: expand telemetry to T5-parity reports and add .join module

- Telemetry: async queued game_start/heartbeat/round_change/game_end with
  sequenced FIFO, watchdog, log-level dvar, and per-player stats snapshot
- Join: new tws_t6_join.gsc chat command lets late spectators enter mid-match
- Update NOTES/README/check.ps1 to reflect the six-module layout

t6/NOTES.md

@@ -15,7 +15,8 @@ config have been removed from this project.
 | Enemy count | Stock `_zm_utility::get_current_zombie_count()` plus queued zombies | Uses the map's zombie team and enemy filters |
 | Timers | Seed elapsed time for late joiners; stop round watcher/reset on game over | T6 timer behavior; keep frozen timers frozen |
 | AFK | Maintain control freeze, disable guns/grenades, guard player state and stale grace threads | Requested movement/shooting fix; retain `.afk` / `.back` and two-second grace |
-| Telemetry | Global `httpPost(url, options)`; no unnecessary common dependency | Avoid raw-loader `http.gsc` and obsolete common-path lookup errors |
+| Telemetry | Global `httpPost(url, options)`; T5-parity queue + heartbeat + game_start/end + watchdog + log-level dvar; per-player `guid` sources from Plutonium's `player.guid` engine property (T5 uses `player getGuid()` method); per-match `kills`/`headshots`/`downs`/`revives` fall back to `0` when `player.stats[]` is unpopulated | T6 has no `getGuid` method but exposes the persistent identity as `.guid` on the player entity; `_zm_stats` writes only into persistent stat storage, so `player.stats[]` is not a stock T6 field. Payload keys match T5 for downstream shape parity |
+| Join | Port of T5 `tws_join.gsc`; uses `level.spawnplayer` / `level.custom_spawnplayer` (lowercase) and `maps\mp\zombies\_zm::spectator_respawn`; readiness gated on `self.sessionstate == "spectator"` instead of T5's `self.initialized` | T6 stock spectator respawn hook lives in `_zm.gsc`; `self.initialized` is a T5 SP zombiemode marker that T6 stock does not populate the same way |
 
 Common retains the T5 HUD constants, helpers and first-spawn dispatcher.
 HUD again owns the `hud_game_over` notification fan-out. Lock again waits on HUD