linear v2: Simple Mode (#7734)

A major, full rewrite of linear mode, now under the name "Simple Mode". 
- Fixes widget styling
- Adds a new simplified history
- Adds support for non-image outputs
- Supports right sidebar
- Allows and panning on the output image preview
- Provides support for drag and drop zones
- Moves workflow notes into a popover.
- Allows scrolling through outputs with Ctrl+scroll or arrow keys

The primary means of accessing Simple Mode is a toggle button on the
bottom right. This button is only shown if a feature flag is enabled, or
the user has already seen linear mode during the current session. Simple
Mode can also be accessed by
- Using the toggle linear mode keybind
- Loading a workflow that that was saved in Simple Mode workflow
- Loading a template url with appropriate parameter

<img width="1790" height="1387" alt="image"
src="https://github.com/user-attachments/assets/d86a4a41-dfbf-41e7-a6d9-146473005606"
/>

Known issues:
- Outputs on cloud are not filtered to those produced by the current
workflow.
  - Output filtering has been globally disabled for consistency
- Outputs will load more items on scroll, but does not unload
- Performance may be reduced on weak devices with very large histories.

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-7734-linear-v2-2d16d73d3650819b8a10f150ff12ea22)
by [Unito](https://www.unito.io)

src/composables/useFeatureFlags.ts

@@ -16,6 +16,7 @@ export enum ServerFeatureFlag {
   PRIVATE_MODELS_ENABLED = 'private_models_enabled',
   ONBOARDING_SURVEY_ENABLED = 'onboarding_survey_enabled',
   HUGGINGFACE_MODEL_IMPORT_ENABLED = 'huggingface_model_import_enabled',
+  LINEAR_TOGGLE_ENABLED = 'linear_toggle_enabled',
   ASYNC_MODEL_UPLOAD_ENABLED = 'async_model_upload_enabled'
 }
 
@@ -77,6 +78,12 @@ export function useFeatureFlags() {
         )
       )
     },
+    get linearToggleEnabled() {
+      return (
+        remoteConfig.value.linear_toggle_enabled ??
+        api.getServerFeature(ServerFeatureFlag.LINEAR_TOGGLE_ENABLED, false)
+      )
+    },
     get asyncModelUploadEnabled() {
       return (
         remoteConfig.value.async_model_upload_enabled ??