feature: mirror all diagnostics to syslog, add VESA fallback for gfxd crashes

- syslogDump now outputs all five diagnostic sections (Fault Info,
  CPU Registers, Process Info, System Info, Call Stack) to serial,
  matching the on-screen BSOD content
- panic() detects if the crash occurred in the gfxd process and
  falls back to rendering the BSOD directly to the VESA framebuffer
  via driver.video text drawing, bypassing LVGL entirely
- Add DrawChar, DrawString, DrawHex, DrawInt to driver.video for
  8x16 bitmap font rendering directly to the framebuffer
- Export SHOULD_CRASH flag from svc.gfxd interface so test commands
  can trigger a deliberate gfxd crash
- Add app.divzero with DIV0, PF, and CRASHGFXD test commands
- Update doc/src/core/core.panic.md and doc/src/driver/video/driver.video.md

src/app/app.divzero.pas

@@ -0,0 +1,57 @@
+{
+    Prog->Ping - ICMP Ping command.
+
+    Sends 10 ICMP echo requests to a host, printing round-trip time
+    for each reply. Sleeps 1 second between pings. Each invocation
+    uses a heap-allocated state record so multiple terminals can app.ping
+    concurrently without corrupting each other.
+
+    @author(Kieron Morris <[email protected]>)
+}
+unit app.divzero;
+
+interface
+
+uses
+    io.stdio, debug.tracer;
+
+procedure init();
+
+implementation
+
+uses
+    arch.x86.bda, driver.net.types, driver.net.proto.icmp, driver.net.util, core.strings,
+    proc.mgr, core.util, arch.x86.util, memory.heap, svc.gfxd;
+
+{ ---- Command entry point (runs as a process) ---- }
+
+procedure run_div0(Params : PParamList; stdin_buf, stdout_buf, stderr_buf : POutBuf);
+begin
+    asm
+        XOR EAX, EAX
+        DIV EAX  { this will trigger a divide by zero exception (interrupt 0) }
+    end;
+end;
+
+procedure run_pf(Params : PParamList; stdin_buf, stdout_buf, stderr_buf : POutBuf);
+begin
+    asm
+        MOV EAX, $DEADBEEF
+        MOV [EAX], EAX  { this will trigger a page fault (interrupt 14) }
+    end;
+end;
+
+procedure run_div0_gfxd(Params : PParamList; stdin_buf, stdout_buf, stderr_buf : POutBuf);
+begin
+    svc.gfxd.SHOULD_CRASH := true;  { set flag to trigger crash in graphics service }
+end;
+
+procedure init();
+begin
+    debug.tracer.push_trace('divzero.init');
+    io.stdio.registerCommand('DIV0', @run_div0, 'Force a divide by zero exception.');
+    io.stdio.registerCommand('PF', @run_pf, 'Force a page fault.');
+    io.stdio.registerCommand('CRASHGFXD', @run_div0_gfxd, 'Force a divide by zero exception in the graphics service.');
+end;
+
+end.

src/app/app.mgr.pas

@@ -33,7 +33,8 @@ uses
     //dispatch
     driver.storage.filedispatch,
     //wasm
-    app.wasm.runner;
+    app.wasm.runner,
+    app.divzero;
 
 { Initialize all baked-in programs }
 procedure init();
@@ -81,6 +82,7 @@ begin
     driver.storage.filedispatch.init();
     app.wasm.runner.init();
     app.setres.init();
+    app.divzero.init();
 end;
 
 end.

src/driver/video/driver.video.pas

@@ -22,7 +22,7 @@ unit driver.video;
 interface
 
 uses
-    memory.heap, debug.tracer, core.gfx.color, driver.video.types, core.ds.hashmap, core.util, arch.x86.util, core.gfx.texture, driver.video.gpu;
+    memory.heap, debug.tracer, core.gfx.color, driver.video.types, core.ds.hashmap, core.util, arch.x86.util, core.gfx.texture, driver.video.gpu, core.gfx.fonts;
 
 procedure init();
 procedure DrawPixel(X : uint32; Y : uint32; Pixel : TRGB32);
@@ -46,6 +46,14 @@ function frontBufferLocation : uint32;
 
 Procedure basicFDrawTexture(Buffer : PVideoBuffer; X : uint32; Y : uint32; Texture : PTexture);
 
+{ Text drawing — renders 8x16 bitmap font glyphs directly to the
+  framebuffer via DrawPixel.  Useful for panic screens and other
+  contexts where LVGL is unavailable. }
+function DrawChar(X, Y : uint32; C : char; Color : TRGB32) : uint32;
+function DrawString(X, Y : uint32; Str : pchar; Color : TRGB32) : uint32;
+function DrawHex(X, Y : uint32; Value : uint32; Color : TRGB32) : uint32;
+function DrawInt(X, Y : uint32; Value : uint32; Color : TRGB32) : uint32;
+
 implementation
 
 uses
@@ -342,6 +350,81 @@ begin
     frontBufferLocation:= VideoInterface.FrontBuffer.Location;
 end;
 
+{ ============================================================
+  Text drawing — 8x16 bitmap font via Std_Font
+  ============================================================ }
+
+const
+    HexChars : array[0..15] of char = '0123456789ABCDEF';
+
+function DrawChar(X, Y : uint32; C : char; Color : TRGB32) : uint32;
+var
+    row, col : uint32;
+    glyphRow : uint8;
+begin
+    for row := 0 to 15 do begin
+        glyphRow := Std_Font[ord(C) * 16 + row];
+        for col := 0 to 7 do begin
+            if (glyphRow AND ($80 SHR col)) <> 0 then
+                DrawPixel(X + col, Y + row, Color);
+        end;
+    end;
+    DrawChar := X + 8;
+end;
+
+function DrawString(X, Y : uint32; Str : pchar; Color : TRGB32) : uint32;
+var
+    i : uint32;
+begin
+    i := 0;
+    while Str[i] <> #0 do begin
+        DrawChar(X, Y, Str[i], Color);
+        X := X + 8;
+        Inc(i);
+    end;
+    DrawString := X;
+end;
+
+function DrawHex(X, Y : uint32; Value : uint32; Color : TRGB32) : uint32;
+var
+    buf : array[0..10] of char;
+    i   : uint32;
+begin
+    buf[0] := '0';
+    buf[1] := 'x';
+    for i := 0 to 7 do
+        buf[2 + i] := HexChars[(Value SHR (28 - i * 4)) AND $F];
+    buf[10] := #0;
+    DrawHex := DrawString(X, Y, @buf[0], Color);
+end;
+
+function DrawInt(X, Y : uint32; Value : uint32; Color : TRGB32) : uint32;
+var
+    buf    : array[0..11] of char;
+    digits : array[0..9] of char;
+    count  : uint32;
+    i      : uint32;
+    tmp    : uint32;
+begin
+    if Value = 0 then begin
+        buf[0] := '0';
+        buf[1] := #0;
+        DrawInt := DrawString(X, Y, @buf[0], Color);
+        exit;
+    end;
+    count := 0;
+    tmp := Value;
+    while tmp > 0 do begin
+        digits[count] := char((tmp mod 10) + ord('0'));
+        tmp := tmp div 10;
+        Inc(count);
+    end;
+    for i := 0 to count - 1 do
+        buf[i] := digits[count - 1 - i];
+    buf[count] := #0;
+    DrawInt := DrawString(X, Y, @buf[0], Color);
+end;
+
 procedure reinit(fb_addr, width, height, pitch : uint32; bpp : uint8);
 begin
     debug.tracer.push_trace('driver.video.reinit.enter');

src/svc/svc.gfxd.pas

@@ -13,6 +13,10 @@ unit svc.gfxd;
 
 interface
 
+var
+    SHOULD_CRASH : boolean;  { set to true to intentionally trigger a crash for testing purposes }
+    
+
 procedure init;
 
 implementation
@@ -56,6 +60,12 @@ begin
             lvgl_handler;
             driver.video.Flush;
         end;
+        if SHOULD_CRASH then begin
+            asm
+                XOR EAX, EAX
+                DIV EAX  { this will trigger a divide by zero exception (interrupt 0) }
+            end;
+        end;
     end;
 end;