refactor: rename Aternos\Mclogs to IndifferentKetchup\Iblogs

Bulk substitution across all PHP files in src/, build.php, worker.php,
and web/frontend/. Updates composer.json's package name and PSR-4
autoload root accordingly. Casing matches the existing
IndifferentKetchup\Codex package's namespace convention (capital K).

Strictly a namespace rename. Aternos\Codex\* imports remain in place;
those get re-pointed in a follow-up commit when the codex Composer
dependency itself is swapped. Filename renames (docker/mclogs.ini,
web/public/css/mclogs.css), README walk-through, env-var prefix changes,
and visible-text branding land in subsequent commits.

composer.json

@@ -1,5 +1,5 @@
 {
-    "name": "aternos/mclogs",
+    "name": "indifferentketchup/iblogs",
     "description": "Paste, share and analyse Minecraft logs",
     "authors": [
         {
@@ -22,7 +22,7 @@
     },
     "autoload": {
         "psr-4": {
-            "Aternos\\Mclogs\\": "src/"
+            "IndifferentKetchup\\Iblogs\\": "src/"
         }
     }
 }