fix(add-page-by-form): patch Grav-2.0 edit-mode header fatal + deploy wiring

Adding a new photo while editing an entry 500s: add-page-by-form's edit branch
reads existing frontmatter via `(array)$page->header()`, but Grav 2.0's
Grav\Common\Page\Header keeps data in a protected `items`, so the cast mangles
keys and `$original_frontmatter['photos']` is never set → array_merge(null,…)
TypeError. Fix: use Header::toArray() (clean keys, stdClass fallback) + guard the
per-field merge. Grav 2.0.7 does not change this — only the plugin fix does.

add-page-by-form is abandoned upstream (last release 2023-09) and its dir is
git-ignored/GPM-managed, so the fix is tracked as deploy/patches/*.patch and
re-applied after any GPM install/update:
- make apply-plugin-patches (local) — chained into install-plugins
- make remote-apply-plugin-patches-{test,prod} — piped over SSH into
  `patch -p1 --forward`; chained into remote-install-plugins / remote-update-plugins
Content syncs don't touch user/plugins/, so the patch survives them; only a GPM
op wipes it (now auto-restored). Runbook + README document the step and a
verify check. Remove once the plugin is forked.

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

docs/working/plans/2026-07-04-frontend-entry-edit.md

@@ -9,7 +9,7 @@ date: 2026-07-04
 
 # Front-End Journal Entry Edit - Plan
 
-**Status:** 🔄 In progress — M1 (U1–U6) complete & verified (V1–V7). M2 **partially delivered** (2026-07-05): **U7 (load existing photos into FilePond) + remove + reorder** are implemented and verified end-to-end on the :8091 container — V9 (photos load, cover-ordered) and V10 (remove a photo, reorder so a different image is the cover; on-disk `photo-1..N` renumber) both pass; reconcile helpers also covered by a reflection unit test (4 cases). One real bug found & fixed en route: `onFormProcessed` fires once per `process:` action (4×), so photo reconciliation is now latched to run **once** (a 2nd pass deleted the just-renamed `photo-N` files). Changes are in `cache-on-save.php` (edit-aware reconcile) + `post-form.js` (U7 load, D1 disable-sweep excludes the FilePond field). **R9 (add NEW photos on edit) is DEFERRED to the form-to-page/image-upload rework** — not by choice: a new upload on edit runs add-page-by-form's edit-mode file merge, which fatals on Grav 2.0 (`(array)$page->header()` yields mangled protected-property keys, so `$original_frontmatter['photos']` is never set → `array_merge(null,…)` TypeError). add-page-by-form is a **stock GPM-managed, git-ignored** plugin (Alt B: no fork), so this can't be patched here; the add affordance is suppressed in edit mode (`allowBrowse/allowDrop` off) so remove/reorder ship cleanly without exposing the fatal. (The earlier Form 9.1.10 filepond "regression" was a separate, already-disproven test artifact — commit `06d9629`.) **Held on the branch for review — not merged / not deployed.**
+**Status:** 🔄 In progress — M1 (U1–U6) complete & verified (V1–V7). M2 **partially delivered** (2026-07-05): **U7 (load existing photos into FilePond) + remove + reorder** are implemented and verified end-to-end on the :8091 container — V9 (photos load, cover-ordered) and V10 (remove a photo, reorder so a different image is the cover; on-disk `photo-1..N` renumber) both pass; reconcile helpers also covered by a reflection unit test (4 cases). One real bug found & fixed en route: `onFormProcessed` fires once per `process:` action (4×), so photo reconciliation is now latched to run **once** (a 2nd pass deleted the just-renamed `photo-N` files). Changes are in `cache-on-save.php` (edit-aware reconcile) + `post-form.js` (U7 load, D1 disable-sweep excludes the FilePond field). **R9 (add NEW photos on edit) now WORKS (2026-07-05)** via a local patch to add-page-by-form. Root cause: its edit-mode merge read existing frontmatter with `(array)$page->header()`, but Grav 2.0's `Grav\Common\Page\Header` keeps data in a protected `items`, so the cast mangled keys (`\0*\0items`) and `$original_frontmatter['photos']` was never set → `array_merge(null,…)` TypeError on any edit that uploads a file. Fix: use `Header::toArray()` (clean keys) + guard the per-field merge. add-page-by-form is abandoned upstream (last release Sept 2023) and its dir is **git-ignored/GPM-managed**, so the patch is tracked as `deploy/patches/add-page-by-form-grav2-header.patch` and re-applied via `make apply-plugin-patches` after any plugin reinstall — until the plugin is forked. Verified end-to-end on :8091: add a photo, remove one, reorder, and all three combined in one save (cover=first, existing preserved, dropped removed); create-with-photos and edit remove/reorder regressions still pass. (Grav 2.0.7 does **not** fix this on its own — the Header object is unchanged across the patch; only the plugin fix does.) **Held on the branch for review — not merged / not deployed.**
 
 ## Goal Capsule