feat(sim): long-press context menu + pixel-perfect real font rendering

Two prototype polish fixes ahead of the website embed work:

1. Holding Enter (the sim's main way into "the rest of the options") did
   nothing -- the JS bridge's sim_enqueue_key() went straight to
   enqueueKey(), bypassing UITask::handleLongPress() entirely, so
   KEY_CONTEXT_MENU could never be reached. Add injectSimKeyLongPress()/
   sim_enqueue_key_longpress(), which does route through the real
   handleLongPress() (same code a real MomentaryButton(pin, 1000, ...)
   reaches), and wire up press-and-hold (buttons + Enter/Space key) in both
   web harnesses with the same 1000ms threshold real hardware uses.

2. SimDisplayDriverCanvas::print() drew text with the browser's own system
   font (ctx.fillText, '8px monospace') instead of the real bitmap font a
   MeshCore-Solo board renders with OLED_MISC_FIXED_FONT=1 (see
   solo/heltec_v3/platformio.ini). Vendor the real Adafruit_GFX (unmodified,
   from the same PlatformIO registry package a real board build pulls) into
   variants/sim/thirdparty/gfx/, and render print() through the real,
   shared src/helpers/ui/MiscFixedRenderer.h + MiscFixedFont.h -- byte-
   identical glyphs to real hardware, not a look-alike.

Verified in a real Chromium (Playwright): short Enter -> "CLOCK TOOLS",
held Enter -> "CLOCK FIELDS" (gotoDashboardConfig(), proving
KEY_CONTEXT_MENU is really reached); font renders as hard square pixels,
inverse/selected-row text still punches correctly through a filled bar.
Full regression re-run clean: all 3 native envs, wasm companion_radio, and
the two-instance + repeater mesh demo (relay routing, DM delivery).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

variants/sim/arduino/Arduino.h

@@ -75,6 +75,20 @@ inline long random(long howsmall, long howbig) {
 #ifndef PROGMEM
 #define PROGMEM
 #endif
+// Real pgm_read_*() on a native host is just a plain dereference -- there's
+// no separate flash address space to special-case. Needed once Adafruit_GFX
+// + MiscFixedFont.h (variants/sim/thirdparty/gfx/, src/helpers/ui/) entered
+// the sim build; nothing before that read PROGMEM data at all (see this
+// file's own header comment).
+#ifndef pgm_read_byte
+#define pgm_read_byte(addr) (*(const uint8_t*)(addr))
+#endif
+#ifndef pgm_read_word
+#define pgm_read_word(addr) (*(const uint16_t*)(addr))
+#endif
+#ifndef pgm_read_dword
+#define pgm_read_dword(addr) (*(const uint32_t*)(addr))
+#endif
 #ifndef F
 #define F(x) (x)
 #endif
@@ -142,6 +156,29 @@ inline void yield() { }
 // declares cleanly, exactly like on a real board.
 class __FlashStringHelper;
 
+// Adafruit_GFX.h declares a getTextBounds(const String&, ...) overload
+// (variants/sim/thirdparty/gfx/) -- MeshCore's own app code never
+// constructs or passes a real Arduino String anywhere (this file's own
+// header comment), so this exists purely to satisfy that one declaration's
+// compile, not to be a real String replacement.
+#include <string>
+class String {
+  std::string _s;
+public:
+  String(const char* s = "") : _s(s ? s : "") {}
+  const char* c_str() const { return _s.c_str(); }
+  size_t length() const { return _s.length(); }
+};
+
+// Real Arduino cores define these; Adafruit_GFX.cpp's drawArc() uses
+// radians(). Same DEG_TO_RAD/RAD_TO_DEG constants as the real macros.
+#ifndef radians
+#define radians(deg) ((deg) * 0.017453292519943295)
+#endif
+#ifndef degrees
+#define degrees(rad) ((rad) * 57.29577951308232)
+#endif
+
 // --- Serial -------------------------------------------------------------
 // Only ever used for Serial.begin() (main.cpp, ignored) and MyMesh.cpp's
 // CLI-rescue debug command handler (Serial.print/println/printf as output,