Add README, customization snapshot, and snapshot/restore tooling

Provisioning now restores all GUI customizations on reset+reprovision:

- create_pod_espocrm.sh: deploy the version-controlled espocrm-custom/ tree
  (CTag entity, layouts, i18n, clientDefs, custom views, custom CSS) into the
  pod, then chown www-data and rebuild. Replaces the earlier inline CSS-only
  step. Adds a live-phase cache rebuild so customizations and the client
  cacheTimestamp are refreshed on every run.
- espocrm-custom/: snapshot of custom/ and client/custom/ (source of truth).
- snapshot_espocrm_custom.sh: refresh the snapshot from a running pod.
- readme.md: usage, first-time host setup, image-update and reset workflows.
- Include the task/instruction notes and plan.md for reference.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

espocrm-custom/client/custom/css/table-var-col.css

@@ -0,0 +1,14 @@
+/**
+ * Variable column widths for Markdown tables in text fields.
+ *
+ * EspoCRM core CSS forces `table-layout: fixed; width: 100%` on
+ * `.complex-text table`, which makes all columns equally wide.
+ * `auto` lets columns size to content instead.
+ *
+ * Registered via custom/Espo/Custom/Resources/metadata/app/client.json (cssList).
+ */
+.complex-text table {
+    table-layout: auto !important;
+    width: auto !important;
+    max-width: 100% !important;
+}