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/symfony/stopwatch/CHANGELOG.md

@@ -0,0 +1,24 @@
+CHANGELOG
+=========
+
+5.2
+---
+
+ * Add `name` argument to the `StopWatchEvent` constructor, accessible via a new `StopwatchEvent::getName()`
+
+5.0.0
+-----
+
+ * Removed support for passing `null` as 1st (`$id`) argument of `Section::get()` method, pass a valid child section identifier instead.
+
+4.4.0
+-----
+
+ * Deprecated passing `null` as 1st (`$id`) argument of `Section::get()` method, pass a valid child section identifier instead.
+
+3.4.0
+-----
+
+ * added the `Stopwatch::reset()` method
+ * allowed to measure sub-millisecond times by introducing an argument to the
+   constructor of `Stopwatch`