show threat budget in debug text overlay

docs/requirements.md

@@ -326,6 +326,10 @@ The screen is divided into three vertical sections:
 
 - REQ-UI-DEBUG-DRAW: A debug draw mode can be toggled on and off with the **M** key (REQ-UI-HOTKEYS). It is inactive by default. While active, the sensor range of every ship — both player and enemy — is drawn as a circle centered on the ship, using that ship schematic's outline color from `visuals.toml`.
 
+- REQ-UI-DEBUG-OVERLAY: While debug draw mode is active (REQ-UI-DEBUG-DRAW), a text overlay is drawn in the upper left corner of the game world view. The overlay has a semi-transparent black background sized to fit its content. It displays the following lines of text:
+  - `Accumulated Threat Level: <level>` — where `<level>` is the current accumulated threat level (see REQ-WAV-THREAT-RATE).
+  - `Time until Wave: <time_s>` — where `<time_s>` is the remaining time in seconds on the normal-wave inter-wave gap timer (see REQ-WAV-GAP). During a quiet window the gap timer is frozen; the displayed value reflects that frozen state.
+
 ### Escape Menu
 
 - REQ-UI-GAME-MENU: Pressing Escape at any time opens the escape menu as a modal dialog and pauses the simulation (sets speed to 0×). On close, the simulation speed is restored to what it was before the menu was opened — so if the game was already paused, it remains paused. The menu contains three buttons:

src/lib/sim/Simulation.cpp

@@ -555,6 +555,11 @@ Tick Simulation::bossCountdownTicks() const
     return m_waveSystem->bossCountdownTicks();
 }
 
+Tick Simulation::normalGapRemainingTicks() const
+{
+    return m_waveSystem->normalGapRemainingTicks();
+}
+
 int Simulation::schematicLevel(const std::string& shipId) const
 {
     const std::map<std::string, SchematicState>::const_iterator it =

src/lib/sim/Simulation.h

@@ -59,7 +59,8 @@ public:
     bool   isGameOver()           const;
     double threatLevel()          const;
     int    bossWaveCounter()      const;
-    Tick   bossCountdownTicks()   const;
+    Tick   bossCountdownTicks()         const;
+    Tick   normalGapRemainingTicks()    const;
 
     // Schematic state queries.
     int  schematicLevel(const std::string& shipId)    const;

src/lib/sim/WaveSystem.cpp

@@ -113,6 +113,11 @@ Tick WaveSystem::bossCountdownTicks() const
     return m_bossCountdownTicks;
 }
 
+Tick WaveSystem::normalGapRemainingTicks() const
+{
+    return m_normalGapRemainingTicks;
+}
+
 // ---------------------------------------------------------------------------
 // Private helpers
 // ---------------------------------------------------------------------------

src/lib/sim/WaveSystem.h

@@ -46,6 +46,10 @@ public:
     // Ticks remaining until the next boss wave fires (REQ-WAV-BOSS-COUNTDOWN).
     Tick bossCountdownTicks() const;
 
+    // Ticks remaining on the current normal-wave gap timer (REQ-WAV-GAP).
+    // Frozen during quiet windows.
+    Tick normalGapRemainingTicks() const;
+
 private:
     struct SpawnEntry
     {

src/ui/GameWorldView.cpp

@@ -292,7 +292,11 @@ void GameWorldView::paintGL()
     drawStations(painter);
     drawBeltItems(painter);
     drawScrap(painter);
-    if (m_debugDraw) { drawDebugSensorRanges(painter); }
+    if (m_debugDraw)
+    {
+        drawDebugSensorRanges(painter);
+        drawDebugOverlay(painter);
+    }
     drawShips(painter);
     drawBeams(painter);
     drawOverlays(painter);
@@ -937,6 +941,38 @@ void GameWorldView::drawDebugSensorRanges(QPainter& painter)
         });
 }
 
+void GameWorldView::drawDebugOverlay(QPainter& painter)
+{
+    painter.resetTransform();
+
+    const QString line1 = tr("Accumulated Threat Level: %1")
+        .arg(m_sim->threatLevel(), 0, 'f', 1);
+    const QString line2 = tr("Time until Wave: %1s")
+        .arg(ticksToSeconds(m_sim->normalGapRemainingTicks()), 0, 'f', 1);
+
+    QFont font = painter.font();
+    font.setPointSize(m_visuals->toast.fontSize);
+    painter.setFont(font);
+
+    const QFontMetrics fm = painter.fontMetrics();
+    const int lineH   = fm.height();
+    const int padding = 8;
+    const int spacing = 4;
+    const int textW   = std::max(fm.horizontalAdvance(line1),
+                                 fm.horizontalAdvance(line2));
+    const int bgW = textW + padding * 2;
+    const int bgH = lineH * 2 + spacing + padding * 2;
+
+    const QRect bgRect(padding, padding, bgW, bgH);
+    painter.fillRect(bgRect, QColor(0, 0, 0, 160));
+
+    painter.setPen(Qt::white);
+    const QRect textRect1(padding * 2, padding + padding, textW, lineH);
+    const QRect textRect2(padding * 2, textRect1.bottom() + spacing, textW, lineH);
+    painter.drawText(textRect1, Qt::AlignLeft | Qt::AlignVCenter, line1);
+    painter.drawText(textRect2, Qt::AlignLeft | Qt::AlignVCenter, line2);
+}
+
 void GameWorldView::drawBeams(QPainter& painter)
 {
     painter.setPen(QPen(m_visuals->beams.color, m_visuals->beams.widthPx));

src/ui/GameWorldView.h

@@ -85,6 +85,7 @@ private:
     void drawScrap(QPainter& painter);
     void drawShips(QPainter& painter);
     void drawDebugSensorRanges(QPainter& painter);
+    void drawDebugOverlay(QPainter& painter);
     void drawBeams(QPainter& painter);
     void drawOverlays(QPainter& painter);
     void drawScreenSpace(QPainter& painter);