fix: address trivial CodeRabbit issues (#9196)

## Summary

Address several trivial CodeRabbit-filed issues: type guard extraction,
ESLint globals, curve editor optimizations, and type relocation.

## Changes

- **What**: Extract `isSingleImage()` type guard in WidgetImageCompare;
add `__DISTRIBUTION__`/`__IS_NIGHTLY__` to ESLint globals and remove
stale disable comments; remove unnecessary `toFixed(4)` from curve path
generation; optimize `histogramToPath` with array join; move
`CurvePoint` type to curve domain

- Fixes #9175
- Fixes #8281
- Fixes #9116
- Fixes #9145
- Fixes #9147

## Review Focus

All changes are mechanical/trivial. Curve path output changes from
fixed-precision to raw floats — SVG handles both fine.

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-9196-fix-address-trivial-CodeRabbit-issues-3126d73d365081f19a5ce20305403098)
by [Unito](https://www.unito.io)

src/components/curve/CurveEditor.test.ts

@@ -1,7 +1,7 @@
 import { mount } from '@vue/test-utils'
 import { describe, expect, it } from 'vitest'
 
-import type { CurvePoint } from '@/lib/litegraph/src/types/widgets'
+import type { CurvePoint } from './types'
 
 import CurveEditor from './CurveEditor.vue'
 

src/components/curve/CurveEditor.vue

@@ -77,7 +77,8 @@
 import { computed, useTemplateRef } from 'vue'
 
 import { useCurveEditor } from '@/composables/useCurveEditor'
-import type { CurvePoint } from '@/lib/litegraph/src/types/widgets'
+
+import type { CurvePoint } from './types'
 
 import { histogramToPath } from './curveUtils'
 

src/components/curve/WidgetCurve.vue

@@ -3,7 +3,7 @@
 </template>
 
 <script setup lang="ts">
-import type { CurvePoint } from '@/lib/litegraph/src/types/widgets'
+import type { CurvePoint } from './types'
 
 import CurveEditor from './CurveEditor.vue'
 

src/components/curve/curveUtils.test.ts

@@ -1,6 +1,6 @@
 import { describe, expect, it } from 'vitest'
 
-import type { CurvePoint } from '@/lib/litegraph/src/types/widgets'
+import type { CurvePoint } from './types'
 
 import {
   createMonotoneInterpolator,

src/components/curve/curveUtils.ts

@@ -1,4 +1,4 @@
-import type { CurvePoint } from '@/lib/litegraph/src/types/widgets'
+import type { CurvePoint } from './types'
 
 /**
  * Monotone cubic Hermite interpolation.
@@ -95,15 +95,15 @@ export function histogramToPath(histogram: Uint32Array): string {
   const max = sorted[Math.floor(255 * 0.995)]
   if (max === 0) return ''
 
-  const step = 1 / 255
-  let d = 'M0,1'
+  const invMax = 1 / max
+  const parts: string[] = ['M0,1']
   for (let i = 0; i < 256; i++) {
-    const x = i * step
-    const y = 1 - Math.min(1, histogram[i] / max)
-    d += ` L${x.toFixed(4)},${y.toFixed(4)}`
+    const x = i / 255
+    const y = 1 - Math.min(1, histogram[i] * invMax)
+    parts.push(`L${x},${y}`)
   }
-  d += ' L1,1 Z'
-  return d
+  parts.push('L1,1 Z')
+  return parts.join(' ')
 }
 
 export function curvesToLUT(points: CurvePoint[]): Uint8Array {

src/components/curve/types.ts

@@ -0,0 +1 @@
+export type CurvePoint = [x: number, y: number]

src/components/custom/widget/WorkflowTemplateSelectorDialog.vue

@@ -438,7 +438,6 @@ onMounted(() => {
 const systemStatsStore = useSystemStatsStore()
 
 const distributions = computed(() => {
-  // eslint-disable-next-line no-undef
   switch (__DISTRIBUTION__) {
     case 'cloud':
       return [TemplateIncludeOnDistributionEnum.Cloud]