Albums: name search and sort by name / modification date

The album grid now shows a filtered + sorted view of the list:
- SQUARE (or tap the header pill) opens the keyboard to filter albums
  by name (case-insensitive); O clears the filter before going back.
- SELECT (or tap the chip) cycles the order: modified newest/oldest,
  name A-Z/Z-A. Uses the album's updatedAt from GET /api/albums.
- Cover eviction no longer drops a texture that a visible card still
  uses when two albums share the same cover photo.
- README: albums controls.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/main.c

@@ -17,6 +17,8 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <strings.h>
+#include <ctype.h>
 #include <stdarg.h>
 #include <math.h>
 #include <setjmp.h>