feat(media-folder-pro): add virtual folder system for WordPress media library

Custom WordPress plugin that replaces the default flat media library with
a structured folder view. Features: hierarchical folders via custom taxonomy,
sidebar folder tree, drag & drop, modal integration with Elementor/builders,
bulk assign, upload auto-assign, toast notifications.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.paul/ROADMAP.md

@@ -0,0 +1,22 @@
+---
+milestone: v0.1 Media Folders MVP
+status: Complete
+---
+
+# v0.1 — Media Folders MVP
+
+Minimalny plugin WordPress z wirtualnymi folderami dla biblioteki mediow.
+
+## Phases
+
+### Phase 1: Plugin Foundation + Taxonomy [Complete]
+Core plugin file, custom taxonomy registration, folder CRUD (create/rename/delete) via AJAX, admin menu integration.
+
+### Phase 2: Media Library Grid Integration [Complete]
+Replace/enhance default media library grid view with folder tree sidebar. Folder filtering, drag & drop media assignment.
+
+### Phase 3: Media Upload Modal Integration [Complete]
+Integrate folder tree into WP media upload modal (used by editor, Elementor, etc.). Allow selecting folder during upload.
+
+### Phase 4: Polish & UX [Complete]
+Bulk operations, folder counters, empty states, confirmations, keyboard navigation, accessibility.