Fix install + admin bugs reported in issue #169

Addresses the five bugs found on master (6e139a1b) during a fresh
Docker install and admin testing:

1. Missing `details` column in gold_fin_log (HTTP 500 on finishing
   construction with gold, buying Gold Club, admin giving gold):
   - Add `details varchar(255)` to the gold_fin_log schema, matching
     every INSERT and the a2b2.php reader that already use it.
   - Fix the broken positional INSERT in Logging::goldFinLog() (it sent
     3 values for a 7-column table) which 500'd on the same gold path.

2. Admin "View Player Info" fatal error: `<? php` -> `<?php` in
   Admin/Templates/playerinfo.tpl.

3. "Reset Server" leaving the DB corrupted (Duplicate key name
   'idx_ft_bonus_xy'): move the croppers indexes inline into the
   CREATE TABLE IF NOT EXISTS so structure recreation is idempotent,
   and add `croppers` to the reset truncate list.

4. Install wizard crash on failed DB connection (mysqli_error(false)):
   use mysqli_connect_error() and show a friendly, actionable message
   (incl. the Docker "db" hostname hint).

5. PHP exposing errors/stack traces to end users: ship a production
   php.ini baseline + docker/php/zz-travianz.ini that turns off
   display_errors and logs to stderr instead.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

GameEngine/Database.php

@@ -462,7 +462,16 @@ class MYSQLi_DB implements IDbConnection {
 	    $this->dbname   = $dbname;
 
 	    // connect to the DB
-	    if (!$this->connect()) die(mysqli_error($this->dblink));
+	    if (!$this->connect()) {
+	        // $this->dblink is FALSE here, so we cannot call mysqli_error() on it.
+	        // Use mysqli_connect_error() and show a friendly, actionable message.
+	        $error = mysqli_connect_error();
+	        die("Database connection failed: " . htmlspecialchars(
+	            $error !== null && $error !== ''
+	                ? $error
+	                : 'could not connect to the database server. Please check the host, port and credentials. (When running with Docker, the database host is usually "db", not "localhost".)'
+	        ));
+	    }
 
 		// we will operate in UTF8
 		mysqli_query($this->dblink,"SET NAMES 'UTF8'");