Implemented client datasource

Client/streamhub/App.h

@@ -26,7 +26,7 @@ namespace StreamHubClient {
 /** One signal as known to the client. */
 struct Signal {
     SignalMeta   meta;
-    SignalBuffer buf{20000};
+    SignalBuffer buf{1000000};
     ImVec4       color{0.4f, 0.8f, 1.0f, 1.0f};
     float        lineWidth = 1.5f;
     int          marker    = -1;   /* ImPlotMarker (-1 = none) */
@@ -244,10 +244,15 @@ public:
     /** @brief Hi-res history zoom cache (per plot, parallel to zoomCache_). */
     PlotZoomCache& histZoomCache(int i) { return histZoomCache_[i]; }
 
+    /* ---- Trigger zoom (per plot, used in trigger capture view) ----------- */
+    bool&  trigZoomed(int i) { return trigZoomed_[i]; }
+    void   resetTrigZoom()   { for (int i = 0; i < kMaxPlotSlots; i++) trigZoomed_[i] = false; }
+
     /** @brief True if the stats panel is open. */
     bool& showStats()    { return showStats_; }
     bool& showAddSrc()   { return showAddSrc_; }
     bool& showTrigBar()  { return showTrigBar_; }
+    bool& showHistBar()  { return showHistBar_; }
 
     /** @brief Find source index by id (-1 if not found). */
     int findSource(const std::string& id) const;
@@ -270,8 +275,8 @@ private:
     void onMaxPointsUpdated(const std::string& json);
 
     /* ---- Rendering ------------------------------------------------------ */
-    void renderMenuBar();
     void renderToolbar();
+    void renderHistoryBar();
     void renderTriggerBar();
     void renderSidebar();
     void renderPlotGrid();
@@ -285,7 +290,7 @@ private:
 
     TriggerState         trigger_;
     PlotLayout           layout_     = PlotLayout::kLayout1x1;
-    uint32_t             maxPoints_  = 20000u;
+    uint32_t             maxPoints_  = 1000000u;
     bool                 globalPaused_ = false;
 
     /* Plot slots: one vector of assignments per plot panel */
@@ -304,6 +309,9 @@ private:
     double cursorA_   = 0.0;
     double cursorB_   = 0.0;
 
+    /* Trigger zoom per plot (capture view zoom state) */
+    bool   trigZoomed_[kMaxPlotSlots] = {};
+
     /* Frozen view per plot (valid while the plot is paused) */
     PlotSnapshot plotSnap_[kMaxPlotSlots];
 
@@ -315,11 +323,13 @@ private:
 
     /* History info from the hub */
     HistoryInfoMsg historyInfo_;
+    double         lastHistInfoReq_ = 0.0;
 
     /* UI state */
     bool showStats_   = false;
     bool showAddSrc_  = false;
     bool showTrigBar_ = false;
+    bool showHistBar_ = false;
     bool sidebarOpen_ = true;
 
     /* Connection fields (populated by init(), editable in menu bar) */