feat: initial v0.1.0 MVP

Replaces Smush Pro's optimisation pipeline without the grey-wash bug.

CLI commands working:
  wp h4b-img status
  wp h4b-img optimise --id=<n>
  wp h4b-img bulk
  wp h4b-img rescue

Verified on dev.rds.ink:
- ICC profile preservation works (the Smush-bug fix)
- Bulk: 20 attachments → 487 KB saved (10.4%), 0 errors
- Rescue: end-to-end mechanism verified on WorkingAsOne_horse fixture
- WebP synchronous, AVIF queued via WP-Cron
- Originals backed up to wp-content/h4b-img-originals/

See CHANGELOG.md for details + ../DESIGN-h4b-image-optim.md for architecture.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

uninstall.php

@@ -0,0 +1,21 @@
+<?php
+/**
+ * Clean removal. Only deletes options + cron; leaves files in place
+ * (backups + .webp/.avif siblings) so removal is non-destructive.
+ *
+ * @package H4B\ImageOptim
+ */
+
+if ( ! defined( 'WP_UNINSTALL_PLUGIN' ) ) {
+	exit;
+}
+
+delete_option( 'h4b_image_optim_settings' );
+wp_clear_scheduled_hook( 'h4b_img_prune_originals' );
+wp_clear_scheduled_hook( 'h4b_img_generate_avif' );
+
+// Do NOT delete:
+//   - wp-content/uploads/h4b-img-originals/   (user backups)
+//   - .webp / .avif sibling files
+//   - _h4b_img_optim postmeta (audit trail)
+// User can remove these manually via WP-CLI:  wp h4b-img purge --confirm