Fix lens.c compile error: add missing Xft/fontconfig headers

- lens.c: add #include <X11/Xft/Xft.h> and <fontconfig/fontconfig.h>
  (XftFont, XGlyphInfo, etc. were declared but the header was never included)
- quill.c: remove unused flen variable in ed_find_next()
- rigel.c: remove unused get_file() helper (get_fidx() is used throughout)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

quill/quill.c

@@ -333,7 +333,6 @@ static void ed_word_right(void) {
 /* find: returns line of next match, -1 if none */
 static int ed_find_next(int from_line, int from_col) {
     if (!ed.find[0]) return -1;
-    int flen = ed.find_len;
     for (int pass = 0; pass < 2; pass++) {
         int start_line = (pass == 0) ? from_line : 0;
         for (int i = start_line; i < ed.nlines; i++) {