feat: add RTL support in epub and txt readers (#1700)

Co-authored-by: Zach Nelson <zach@zdnelson.com>

lib/MiniBidi/bidi_pairs.t

@@ -0,0 +1,39 @@
+/* bidi_pairs.t — unified mirror + bracket table for CrossPoint.
+ *
+ * Replaces both mirroring.t and brackets.t.  canonical.t is dropped
+ * (fullwidth brackets are not used in Hebrew epub content).
+ *
+ * Each entry: {from, to, bracket_type}
+ *   bracket_type == BRACKo : `from` is an opening bracket
+ *   bracket_type == BRACKc : `from` is a closing bracket; `to` = opener
+ *   bracket_type == BRACKx : not a bracket pair — mirrored by rule L4 only
+ *
+ * mirror(c)  → always returns `to` for any entry where c==from
+ * bracket(c) → returns 0 for BRACKx; c for BRACKo; `to` (opener) for BRACKc
+ *
+ * Sorted ascending by `from` (binary search).
+ */
+
+/* ASCII brackets — both bracket pairs AND L4 mirrors */
+{0x0028, 0x0029, BRACKo},   /* ( */
+{0x0029, 0x0028, BRACKc},   /* ) */
+{0x003C, 0x003E, BRACKo},   /* < */
+{0x003E, 0x003C, BRACKc},   /* > */
+{0x005B, 0x005D, BRACKo},   /* [ */
+{0x005D, 0x005B, BRACKc},   /* ] */
+{0x007B, 0x007D, BRACKo},   /* { */
+{0x007D, 0x007B, BRACKc},   /* } */
+
+/* Angle quotation marks — L4 mirror only */
+{0x00AB, 0x00BB, BRACKx},   /* « → » */
+{0x00BB, 0x00AB, BRACKx},   /* » → « */
+
+/* Curly quotes — L4 mirror only */
+{0x2018, 0x2019, BRACKx},   /* ' → ' */
+{0x2019, 0x2018, BRACKx},   /* ' → ' */
+{0x201C, 0x201D, BRACKx},   /* " → " */
+{0x201D, 0x201C, BRACKx},   /* " → " */
+
+/* Single angle quotes */
+{0x2039, 0x203A, BRACKo},   /* ‹ → › */
+{0x203A, 0x2039, BRACKc},   /* › → ‹ */