[Client/Server/Protocol] Surface live metrics in the Developer tab (#7212)

* [Server] Instrument command processing, game starts, and event loops

Add a lock-free MetricsRegistry that accumulates per-command processing
times in preallocated histogram slots (one per protobuf command type,
bucketed at 1/5/10/25/50/100/250/500/1000/2500/5000 ms +Inf). The
hot-path observeCommand() uses only relaxed atomic adds — no locks,
no allocations, no cache-line ping-pong beyond the unavoidable counter
updates.

Wire the registry into AbstractServerSocketInterface::processCommandContainer()
so every processed command is attributed with its container's wall-clock
time. When a container exceeds metrics/slow_command_ms (default 500),
a warning is logged including the connected username.

Add an EventLoopWatchdog heartbeat that runs on every socket pool thread.
If a heartbeat overshoots metrics/stall_warn_ms (default 2000 ms), the
overshoot is recorded in atomic counters and a warning is logged. Both
thresholds are configurable in servatrice.ini; setting stall_warn_ms to 0
disables the watchdogs entirely.

Track game-start durations via a separate histogram in MetricsRegistry.
Server_Game::startGameNow() measures the time from zone creation through
player materialization and reports it via Server::observeGameStartDurationMs().

Add a live card-count gauge: Server_Game exposes getCardsInGame() and
Servatrice::getCardsInGamesTotal() sums across all running games under
the appropriate read locks.

Include a standalone metrics_registry_test (Google Test) that validates
empty registries, single/multi-sample histograms, kind encoding,
overflow-slot collapse, negative-duration clamping, gauge rendering,
and the game-start histogram separation.

Took 10 minutes

* [Client/Server/Protocol] Surface live metrics in the Developer tab

Extend Response_GetServerStats with live counters from the in-process
MetricsRegistry: cards in games, event loop stall totals/worst,
total commands processed, average command time, active command types,
and game-start count/duration. Add a repeated CommandStats message
carrying per-command breakdowns (kind, extension number, resolved
protobuf name, count, total ms) for every type that has seen at
least one sample.

Server-side cmdGetServerStats() populates all new fields after the
existing DB uptime snapshot query, resolving protobuf extension names
via the descriptor pool for human-readable labels like
session/Command_Ping.

Expand TabDeveloper with two tables: an overview section (existing
DB stats plus the new live metrics) and a per-command breakdown table
(Command / Count / Total ms / Avg ms) sorted by total_ms descending
so the hottest commands surface first.

Took 55 minutes

Took 47 seconds

* [Server] Drop dead Prometheus histogram, add developer command metrics, fix watchdog init order

- metrics_registry: remove toPrometheusText/appendCumulativeBuckets and the time-bucket histogram that nothing in production ever emitted (the future /metrics exporter can bring it back); keep counts/totals read by the Developer tab
- Fix +Inf bucket routing that never incremented, and its test that locked the bug in
- Instrument developer_command container (kind 6) in processCommandContainer and stats label resolution
- Read metrics/{slow_command_ms,stall_warn_ms} at the top of initServer() so stall_warn_ms=0 disables the watchdogs before pool threads start
- Shrink KindStride to 1280 (largest extension in use is 1206) with a static_assert; document scrape cost of getCardsInGamesTotal; note slow_command logging has no rate limit in servatrice.ini.example

* [Tests] Give metrics_registry_test an explicit main

* [Server] Record only the dispatched command family; drop unused totals

processCommandContainer recorded every family in a container even though
the base if/else-if dispatch processes at most one. An unauthenticated
client could batch a session command (login) with fabricated developer,
moderator, and admin entries and forge genuine-looking samples that were
never executed or authorized. Mirror the base's selection, skip when the
handler was already deleted, and skip entries whose extension number is
-1 (which would otherwise wrap into the previous kind's id range).

[Server] Drop dead process-lifetime byte/uptime counters

txBytesTotal/rxBytesTotal added an atomic RMW to every socket write and
read for counters nothing consumes (cmdGetServerStats fills tx_bytes,
rx_bytes, and uptime_secs from the DB snapshot). Remove the two atomics
and the getTxBytesTotal/getRxBytesTotal/getUptimeSeconds getters; the
incTxBytes/incRxBytes slots and mutexes remain for the ISL legacy
counters.

[Protocol] Document kind 5 as developer in CommandStats

NumKinds is 6 and the server emits kind_index = 5 for developer
commands; the comment stopped at 4.

* [Client] Togglable auto-refresh for Developer stats tab

* [Oracle] Fix clang-format alignment of card type priority list

---------

Co-authored-by: Lukas Brübach <Bruebach.Lukas@bdosecurity.de>

servatrice/src/event_loop_watchdog.cpp

@@ -0,0 +1,34 @@
+/**
+ * @file event_loop_watchdog.cpp
+ * @ingroup Servatrice
+ */
+
+#include "event_loop_watchdog.h"
+
+#include "servatrice.h"
+
+#include <QTimer>
+
+EventLoopWatchdog::EventLoopWatchdog(Servatrice *_servatrice, QString _threadName)
+    : QObject(nullptr), servatrice(_servatrice), threadName(std::move(_threadName))
+{
+}
+
+void EventLoopWatchdog::start()
+{
+    heartbeatTimer = new QTimer(this);
+    sinceLastTick.start();
+    connect(heartbeatTimer, &QTimer::timeout, this, &EventLoopWatchdog::checkHeartbeat);
+    heartbeatTimer->start(HeartbeatIntervalMs);
+}
+
+void EventLoopWatchdog::checkHeartbeat()
+{
+    const qint64 elapsedMs = sinceLastTick.restart();
+    const qint64 overshootMs = qMax<qint64>(0, elapsedMs - HeartbeatIntervalMs);
+    if (overshootMs < servatrice->getMetricsStallWarnMs()) {
+        return;
+    }
+
+    servatrice->observeEventLoopStall(threadName, overshootMs);
+}