feat: initial implementation of Focus RSVP speed reader

- Pure frontend SPA (Vite + React 19 + TypeScript + Tailwind CSS v4)
- Spritz ORP engine with absolute center crosshair gaze fixation
- Multilingual hybrid segmentation via Intl.Segmenter with punctuation attachment
- Adaptive breathing rhythm delay algorithm for natural comprehension
- IndexedDB local bookshelf, progress persistence, and client-side EPUB/TXT/MD parsing
- Curated sci-fi, philosophy, and classic speech samples
- Dark/OLED/Sepia/Slate/Nord themes and rich keyboard controls

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

src/core/orp.ts

@@ -0,0 +1,74 @@
+/**
+ * Optimal Recognition Point (ORP) Calculation for Spritz RSVP Reading.
+ * Fixates the eye at ~30%-35% into the word where human ocular fixation naturally rests.
+ */
+
+const CJK_REGEX = /[一-龥぀-ヿ가-힯]/;
+
+export function isCJKChar(char: string): boolean {
+  return CJK_REGEX.test(char);
+}
+
+export function isCJKWord(word: string): boolean {
+  return CJK_REGEX.test(word);
+}
+
+/**
+ * Calculates the 0-based index of the ORP character in cleanWord.
+ */
+export function calculateOrpIndex(cleanWord: string): number {
+  const len = cleanWord.length;
+  if (len <= 1) return 0;
+
+  if (isCJKWord(cleanWord)) {
+    // CJK characters have high semantic density per glyph
+    if (len === 2) return 0;
+    if (len <= 4) return 1;
+    if (len <= 6) return 2;
+    return Math.min(len - 1, Math.floor((len - 1) * 0.35));
+  }
+
+  // Standard Spritz ORP Table for alphabetic words
+  if (len <= 5) return 1;
+  if (len <= 9) return 2;
+  if (len <= 13) return 3;
+  return 4;
+}
+
+export interface SplitWord {
+  prefix: string;
+  pivot: string;
+  suffix: string;
+  orpIndex: number;
+}
+
+/**
+ * Splits a token into prefix, pivot (ORP character), and suffix.
+ * Handles leading punctuation (e.g. "“", "《", "(") and trailing punctuation.
+ */
+export function splitOrp(
+  coreWord: string,
+  leadingPunct: string = '',
+  trailingPunct: string = ''
+): SplitWord {
+  if (!coreWord) {
+    return {
+      prefix: leadingPunct,
+      pivot: '',
+      suffix: trailingPunct,
+      orpIndex: 0,
+    };
+  }
+
+  const orpIndex = calculateOrpIndex(coreWord);
+  const prefix = leadingPunct + coreWord.slice(0, orpIndex);
+  const pivot = coreWord[orpIndex] || '';
+  const suffix = coreWord.slice(orpIndex + 1) + trailingPunct;
+
+  return {
+    prefix,
+    pivot,
+    suffix,
+    orpIndex,
+  };
+}