fix(editor): stabilize image generation, layer editing and controls (#6992)

* fix(editor): stabilize image workflows and editing controls

* docs(editor): add desktop and mobile visual validation evidence

* fix(editor): synchronize quick edit model events and register imagePreferences in test coordinator

* fix(settings): enforce authoritative global image-gen policy and non-admin preference persistence

- Enforce authoritative administrator global image_gen_enabled disable in get_user_setting, do_generate_image, and image_editing_provider_available, preventing non-admin user preference overrides while preserving user-disabled opt-outs and can_generate_images privilege checks across direct, gallery, and editor paths.
- Filter non-admin preference persistence in saveImagePreferences to user preference keys only (image_model, image_edit_model, image_quality), preventing global policy toggles from leaking into user preferences.
- Return accurate 200 OK Response from saveImagePreferences after fallback persistence succeeds so settings UI displays 'Saved' instead of false 403 error, while retaining visibility of real errors.
- Load per-user preferences via readImagePreferences in initImageSettings so non-admin selections persist and display correctly after page reload.
- Clear per-user model preferences on successful admin save (POST /api/auth/settings) via PUT /api/prefs/{key} with value: null to prevent stale per-user preferences from shadowing updated global settings.
- Support clearing keys in PUT /api/prefs/{key} when value is null.
- Add comprehensive Python regression tests for global-disabled/user-enabled, global-enabled/user-disabled, and authorized generation, plus Node and browser regression tests for non-admin persistence, toggle isolation, reload, and admin clearing.

* fix(settings): invalidate shared appConfig cache near auth settings write

* fix(test): isolate test_tool_policy unit suite from external model endpoint state

* fix(test): isolate web_fetch failure regression from contextual follow-up heuristics

* fix(test): isolate test_tool_policy from cross-test approval gate state

Ensure _patch_loop_basics disables TOOL_APPROVAL_GATE_ENABLED so routing tests in test_tool_policy run in the intended opt-out posture even when prior tests populate DATA_DIR with skills or untrusted context. Remove unnecessary forced_tools and contextual web mock workarounds.

* fix(settings): isolate non-admin image toggle and surface preference cleanup errors

- Restrict image generation availability toggle to admin users in imageModels.js, disabling the switch for non-admins and reverting unauthorized changes with an explicit message.
- Separate non-admin image model preference saves from global toggle updates.
- Track preference cleanup results on admin save in imagePreferences.js, propagating cleanup failures instead of ignoring them.
- Require valid preference keys on 403 fallback so toggle-only attempts reject cleanly.
- Add /api/prefs route mock to test_image_model_settings_sync_both_directions_and_survive_reopening.
- Add regression coverage for admin cleanup failures and non-admin toggle rejection.

* fix(settings): reconcile admin toggle on partial cleanup failure and report errors

- In imagePreferences.js, distinguish pre-persistence failures from post-save cleanup failures using err.globalSaved and err.phase.

- In imagePreferences.js, notify listeners of global policy updates on partial success before propagating cleanup failure.

- In imageModels.js, retain the persisted target state on admin toggle when global persistence succeeds but cleanup fails.

- In imageModels.js, reconcile admin toggle with authoritative server state via readImagePreferences() after ambiguous or partial failures.

- In imageModels.js, report partial success accurately without suppressing preference cleanup error messages.

- Add regression coverage in test_settings_save_response_ok_js.py for cleanup HTTP 500, cleanup network rejection, successful cleanup, and failed global POST.

---------

Co-authored-by: pewdiepie-archdaemon <pewdiepie-archdaemon@users.noreply.github.com>
Co-authored-by: Alexandre Teixeira <general@alexandreteixeira.dev>

static/js/editor/ai-tool-runner.js

@@ -76,7 +76,12 @@ export function createApplyImageTool({
         if (sel.endpoint) extraPayload._endpoint = sel.endpoint;
         if (sel.model && !extraPayload._model) extraPayload._model = sel.model;
       }
-      const flatCanvas = flatten();
+      const removeBackground = endpoint === '/api/image/remove-bg';
+      const targetLayer = removeBackground ? state.layers.find(layer => layer.id === state.activeLayerId) : null;
+      if (removeBackground && (!targetLayer?.canvas || targetLayer.kind === 'adjustment' || targetLayer.locks?.pixels)) {
+        throw new Error('Select an unlocked image layer first');
+      }
+      const flatCanvas = removeBackground ? targetLayer.canvas : flatten();
       const imageB64 = flatCanvas.toDataURL('image/png').split(',')[1];
       const body = { image: imageB64, ...extraPayload };
       const res = await fetch(endpoint, {
@@ -96,6 +101,23 @@ export function createApplyImageTool({
       const img = await decodeAIImage(data.image, operation.signal);
       operation.signal.throwIfAborted();
       if (!state.editorOpen) return; // user closed mid-decode (v2 review HIGH-4)
+      if (removeBackground) {
+        if (!state.layers.includes(targetLayer)) return;
+        saveState('Remove background');
+        // The returned pixels replace the editable source, not just its preview.
+        targetLayer.kind = 'raster';
+        targetLayer.placed = null;
+        targetLayer.text = null;
+        targetLayer.shape = null;
+        targetLayer.ctx.clearRect(0, 0, targetLayer.canvas.width, targetLayer.canvas.height);
+        targetLayer.ctx.drawImage(img, 0, 0, targetLayer.canvas.width, targetLayer.canvas.height);
+        targetLayer._adjCacheKey = null;
+        targetLayer._adjFinalKey = null;
+        composite();
+        renderLayerPanel();
+        uiModule?.showToast('Background removed');
+        return targetLayer;
+      }
       {
         saveState();
         const layer = createLayer(layerName, state.imgWidth, state.imgHeight);