refactor: Cleanup git state - commit all staged changes

Major refactoring cleanup:
- Add new controller architecture (class-controller-*.php)
- Add new settings-v2 UI (views/settings-v2/)
- Add new CSS architecture (agentic-sidebar.css, tokens)
- Add esbuild build pipeline (scripts/build.js, package.json)
- Add composer dependencies (vendor/)
- Add frontend src directory (assets/js/src/index.jsx)
- Add documentation files
- Remove old/obsolete files (class-settings.php, old CSS)

This commits all pending changes from previous refactoring efforts.

vendor/jawira/plantuml-encoding/LICENSE.md

@@ -0,0 +1,21 @@
+MIT License
+===========
+
+**Copyright (c) 2017-2021 Jawira Portugal**
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the “Software”), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+the Software, and to permit persons to whom the Software is furnished to do so,
+subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

vendor/jawira/plantuml-encoding/composer.json

@@ -0,0 +1,35 @@
+{
+  "name": "jawira/plantuml-encoding",
+  "description": "PlantUML encoding functions",
+  "license": "MIT",
+  "type": "library",
+  "keywords": [
+    "PlantUML",
+    "functions",
+    "encoding",
+    "encodep",
+    "uml"
+  ],
+  "authors": [
+    {
+      "name": "Jawira Portugal",
+      "homepage": "https://jawira.com"
+    }
+  ],
+  "require": {
+    "php": ">=7.4",
+    "ext-zlib": "*"
+  },
+  "require-dev": {
+    "phpstan/phpstan": "^2"
+  },
+  "autoload": {
+    "files": [
+      "src/plantuml_functions.php"
+    ]
+  },
+  "config": {
+    "preferred-install": "dist",
+    "sort-packages": true
+  }
+}

vendor/jawira/plantuml-encoding/src/plantuml_functions.php

@@ -0,0 +1,98 @@
+<?php declare(strict_types=1);
+
+namespace Jawira\PlantUml;
+
+/**
+ * Encodes a UML text description into a special encoding.
+ *
+ * @param string $puml PlantUml diagram code, expected to be UTF-8.
+ *
+ * @return string Encoded string
+ * @throws \RuntimeException Error with gzdeflate()
+ */
+function encodep(string $puml): string
+{
+    $compressed = gzdeflate($puml, 9);
+
+    if (false === $compressed) {
+        throw new \RuntimeException('Error while compressing PlantUml diagram.');
+    }
+
+    return encode64($compressed);
+}
+
+/**
+ * @param string $compressed Compressed string
+ *
+ * @return string Encoded string
+ */
+function encode64(string $compressed): string
+{
+    $encoded = '';
+    $length = mb_strlen($compressed, '8bit');
+    for ($i = 0; $i < $length; $i += 3) {
+        switch ($length) {
+            case $i + 1:
+                $encoded .= append3bytes(ord($compressed[$i]), 0, 0);
+                break;
+            case $i + 2:
+                $encoded .= append3bytes(ord($compressed[$i]), ord($compressed[$i + 1]), 0);
+                break;
+            default:
+                $encoded .= append3bytes(ord($compressed[$i]), ord($compressed[$i + 1]), ord($compressed[$i + 2]));
+                break;
+        }
+    }
+
+    return $encoded;
+}
+
+/**
+ * @param int $b1 First byte
+ * @param int $b2 Second byte
+ * @param int $b3 Third byte
+ *
+ * @return string
+ */
+function append3bytes(int $b1, int $b2, int $b3): string
+{
+    $c1 = $b1 >> 2;
+    $c2 = (($b1 & 0x3) << 4) | ($b2 >> 4);
+    $c3 = (($b2 & 0xF) << 2) | ($b3 >> 6);
+    $c4 = $b3 & 0x3F;
+    $r = encode6bit($c1 & 0x3F);
+    $r .= encode6bit($c2 & 0x3F);
+    $r .= encode6bit($c3 & 0x3F);
+    $r .= encode6bit($c4 & 0x3F);
+
+    return $r;
+}
+
+/**
+ * @param int $b
+ *
+ * @return string
+ */
+function encode6bit(int $b): string
+{
+    if ($b < 10) {
+        return chr(48 + $b);
+    }
+    $b -= 10;
+    if ($b < 26) {
+        return chr(65 + $b);
+    }
+    $b -= 26;
+    if ($b < 26) {
+        return chr(97 + $b);
+    }
+    $b -= 26;
+    if ($b === 0) {
+        return '-';
+    }
+    if ($b === 1) {
+        return '_';
+    }
+
+    return '?';
+}