feat: add reset-to-default for widget parameters in right side panel (#8861)

## Summary

Add per-widget and reset-all-parameters functionality to the right side
panel, allowing users to quickly revert widget values to their defaults.

## Changes

- **What**: Per-widget "Reset to default" option in the WidgetActions
overflow menu, plus a "Reset all parameters" button in each
SectionWidgets header. Defaults are derived from the InputSpec (explicit
default, then type-specific fallbacks: 0 for INT/FLOAT, false for
BOOLEAN, empty string for STRING, first option for COMBO).
- **Dependencies**: Builds on #8594 (WidgetValueStore) for reactive UI
updates after reset.

## Review Focus

- `getWidgetDefaultValue` fallback logic in `src/utils/widgetUtil.ts` —
are the type-specific defaults appropriate?
- Deep equality check (`isEqual`) for disabling the reset button when
the value already matches the default.
- Event flow: WidgetActions emits `resetToDefault` → WidgetItem forwards
→ SectionWidgets handles via `writeWidgetValue` (sets value, triggers
callback, marks canvas dirty).

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-8861-feat-add-reset-to-default-for-widget-parameters-in-right-side-panel-3076d73d365081d1aa08d5b965a16cf4)
by [Unito](https://www.unito.io)

Co-authored-by: Terry Jia <terryjia88@gmail.com>

src/locales/en/main.json

@@ -2953,7 +2953,9 @@
     "nodesNoneDesc": "NO NODES",
     "fallbackGroupTitle": "Group",
     "fallbackNodeTitle": "Node",
-    "hideAdvancedInputsButton": "Hide advanced inputs"
+    "hideAdvancedInputsButton": "Hide advanced inputs",
+    "resetToDefault": "Reset to default",
+    "resetAllParameters": "Reset all parameters"
   },
   "help": {
     "recentReleases": "Recent releases",