fix: enable enforce-canonical-classes tailwind lint rule (#9427)

## Summary

Enable `better-tailwindcss/enforce-canonical-classes` lint rule and
auto-fix all 611 violations across 173 files. Stacked on #9417.

## Changes

- **What**: Simplify Tailwind classes to canonical forms via `eslint
--fix`:
  - `h-X w-X` → `size-X`
  - `overflow-x-hidden overflow-y-hidden` → `overflow-hidden`
  - and other canonical simplifications
- Enable `enforce-canonical-classes` as `'error'` in eslint config

## Review Focus

Mechanical auto-fix PR — all changes produced by `eslint --fix`. No
visual or behavioral changes; canonical forms are functionally
identical.

**Stack:** #9417 → **this PR** → PR 3 (class order)

Fixes #9300 (partial — 2 of 3 rules)

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-9427-fix-enable-enforce-canonical-classes-tailwind-lint-rule-31a6d73d365081a49340d7d4640ede45)
by [Unito](https://www.unito.io)

src/components/maskeditor/controls/DropdownControl.vue

@@ -1,6 +1,6 @@
 <template>
   <div class="flex flex-row gap-2.5 items-center min-h-6 relative">
-    <span class="text-left text-xs font-sans text-[var(--descrip-text)]">{{
+    <span class="text-left text-xs font-sans text-(--descrip-text)">{{
       label
     }}</span>
     <select

src/components/maskeditor/controls/SliderControl.vue

@@ -1,6 +1,6 @@
 <template>
   <div class="flex flex-col gap-3 pb-3">
-    <span class="text-left text-xs font-sans text-[var(--descrip-text)]">{{
+    <span class="text-left text-xs font-sans text-(--descrip-text)">{{
       label
     }}</span>
     <input

src/components/maskeditor/controls/ToggleControl.vue

@@ -1,6 +1,6 @@
 <template>
   <div class="flex flex-row gap-2.5 items-center min-h-6 relative">
-    <span class="text-left text-xs font-sans text-[var(--descrip-text)]">{{
+    <span class="text-left text-xs font-sans text-(--descrip-text)">{{
       label
     }}</span>
     <label class="maskEditor_sidePanelToggleContainer">