feat: Add dictionary word lookup feature with cached index

Implements StarDict-based dictionary lookup from the reader menu,
adapted from upstream PR #857 with /.dictionary/ folder path,
std::vector compatibility (PR #802), HTML definition rendering,
orientation-aware button hints, side button hints with CCW text
rotation, sparse index caching to SD card, pronunciation line
filtering, and reorganized reader menu with bookmark stubs.

Co-authored-by: Cursor <cursoragent@cursor.com>

lib/GfxRenderer/GfxRenderer.cpp

@@ -905,6 +905,92 @@ void GfxRenderer::drawTextRotated90CW(const int fontId, const int x, const int y
   }
 }
 
+void GfxRenderer::drawTextRotated90CCW(const int fontId, const int x, const int y, const char* text, const bool black,
+                                       const EpdFontFamily::Style style) const {
+  // Cannot draw a NULL / empty string
+  if (text == nullptr || *text == '\0') {
+    return;
+  }
+
+  if (fontMap.count(fontId) == 0) {
+    Serial.printf("[%lu] [GFX] Font %d not found\n", millis(), fontId);
+    return;
+  }
+  const auto font = fontMap.at(fontId);
+
+  // No printable characters
+  if (!font.hasPrintableChars(text, style)) {
+    return;
+  }
+
+  // For 90° counter-clockwise rotation:
+  // Mirror of CW: glyphY maps to -X direction, glyphX maps to +Y direction
+  // Text reads from top to bottom
+
+  const int advanceY = font.getData(style)->advanceY;
+  const int ascender = font.getData(style)->ascender;
+
+  int yPos = y;  // Current Y position (increases as we draw characters)
+
+  uint32_t cp;
+  while ((cp = utf8NextCodepoint(reinterpret_cast<const uint8_t**>(&text)))) {
+    const EpdGlyph* glyph = font.getGlyph(cp, style);
+    if (!glyph) {
+      glyph = font.getGlyph(REPLACEMENT_GLYPH, style);
+    }
+    if (!glyph) {
+      continue;
+    }
+
+    const int is2Bit = font.getData(style)->is2Bit;
+    const uint32_t offset = glyph->dataOffset;
+    const uint8_t width = glyph->width;
+    const uint8_t height = glyph->height;
+    const int left = glyph->left;
+    const int top = glyph->top;
+
+    const uint8_t* bitmap = &font.getData(style)->bitmap[offset];
+
+    if (bitmap != nullptr) {
+      for (int glyphY = 0; glyphY < height; glyphY++) {
+        for (int glyphX = 0; glyphX < width; glyphX++) {
+          const int pixelPosition = glyphY * width + glyphX;
+
+          // 90° counter-clockwise rotation transformation:
+          // screenX = mirrored CW X (right-to-left within advanceY span)
+          // screenY = yPos + (left + glyphX) (downward)
+          const int screenX = x + advanceY - 1 - (ascender - top + glyphY);
+          const int screenY = yPos + left + glyphX;
+
+          if (is2Bit) {
+            const uint8_t byte = bitmap[pixelPosition / 4];
+            const uint8_t bit_index = (3 - pixelPosition % 4) * 2;
+            const uint8_t bmpVal = 3 - (byte >> bit_index) & 0x3;
+
+            if (renderMode == BW && bmpVal < 3) {
+              drawPixel(screenX, screenY, black);
+            } else if (renderMode == GRAYSCALE_MSB && (bmpVal == 1 || bmpVal == 2)) {
+              drawPixel(screenX, screenY, false);
+            } else if (renderMode == GRAYSCALE_LSB && bmpVal == 1) {
+              drawPixel(screenX, screenY, false);
+            }
+          } else {
+            const uint8_t byte = bitmap[pixelPosition / 8];
+            const uint8_t bit_index = 7 - (pixelPosition % 8);
+
+            if ((byte >> bit_index) & 1) {
+              drawPixel(screenX, screenY, black);
+            }
+          }
+        }
+      }
+    }
+
+    // Move to next character position (going down, so increase Y)
+    yPos += glyph->advanceX;
+  }
+}
+
 uint8_t* GfxRenderer::getFrameBuffer() const { return frameBuffer; }
 
 size_t GfxRenderer::getBufferSize() { return HalDisplay::BUFFER_SIZE; }

lib/GfxRenderer/GfxRenderer.h

@@ -111,9 +111,11 @@ class GfxRenderer {
   std::string truncatedText(int fontId, const char* text, int maxWidth,
                             EpdFontFamily::Style style = EpdFontFamily::REGULAR) const;
 
-  // Helper for drawing rotated text (90 degrees clockwise, for side buttons)
+  // Helpers for drawing rotated text (for side buttons)
   void drawTextRotated90CW(int fontId, int x, int y, const char* text, bool black = true,
                            EpdFontFamily::Style style = EpdFontFamily::REGULAR) const;
+  void drawTextRotated90CCW(int fontId, int x, int y, const char* text, bool black = true,
+                            EpdFontFamily::Style style = EpdFontFamily::REGULAR) const;
   int getTextHeight(int fontId) const;
 
   // Grayscale functions