Use a Unicode collation for SQLite

lib/Db/SQLite3/Driver.php

@@ -57,6 +57,10 @@ class Driver extends \JKingWeb\Arsse\Db\AbstractDriver {
         $this->setTimeout($timeout);
         // set other initial options
         $this->exec("PRAGMA foreign_keys = yes");
+        // use a case-insensitive Unicode collation sequence
+        $this->collator = new \Collator("@kf=false");
+        $m = ($this->db instanceof \PDO) ? "sqliteCreateCollation" : "createCollation";
+        $this->db->$m("nocase", [$this->collator, "compare"]);
     }
 
     public static function requirementsMet(): bool {

sql/PostgreSQL/2.sql

@@ -4,9 +4,7 @@
 
 -- Please consult the SQLite 3 schemata for commented version
 
--- create a case-insensitive generic collation sequence
--- this collation is Unicode-aware, whereas SQLite's built-in nocase 
--- collation is ASCII-only
+-- create a case-insensitive generic Unicode collation sequence
 create collation nocase(
     provider = icu,
     locale = '@kf=false'

sql/SQLite3/3.sql

@@ -19,6 +19,9 @@ create table arsse_marks(
 insert into arsse_marks select article,subscription,read,starred,modified,note,0 from arsse_marks_old;
 drop table arsse_marks_old;
 
+-- reindex anything which uses the nocase collation sequence; it has been replaced with a Unicode collation
+reindex nocase;
+
 -- set version marker
 pragma user_version = 4;
 update arsse_meta set value = '4' where key = 'schema_version';