asdf

Squash the current repository state back into one baseline commit while
preserving the README reframing and repository contents.

Constraint: User explicitly requested a single squashed commit with subject "asdf"
Confidence: high
Scope-risk: broad
Reversibility: clean
Directive: This commit intentionally rewrites published history; coordinate before future force-pushes
Tested: git status clean; local history rewritten to one commit; force-pushed main to origin and instructkr
Not-tested: Fresh clone verification after push

src/components/StructuredDiff/colorDiff.ts

@@ -0,0 +1,37 @@
+import {
+  ColorDiff,
+  ColorFile,
+  getSyntaxTheme as nativeGetSyntaxTheme,
+  type SyntaxTheme,
+} from 'color-diff-napi'
+import { isEnvDefinedFalsy } from '../../utils/envUtils.js'
+
+export type ColorModuleUnavailableReason = 'env'
+
+/**
+ * Returns a static reason why the color-diff module is unavailable, or null if available.
+ * 'env' = disabled via CLAUDE_CODE_SYNTAX_HIGHLIGHT
+ *
+ * The TS port of color-diff works in all build modes, so the only way to
+ * disable it is via the env var.
+ */
+export function getColorModuleUnavailableReason(): ColorModuleUnavailableReason | null {
+  if (isEnvDefinedFalsy(process.env.CLAUDE_CODE_SYNTAX_HIGHLIGHT)) {
+    return 'env'
+  }
+  return null
+}
+
+export function expectColorDiff(): typeof ColorDiff | null {
+  return getColorModuleUnavailableReason() === null ? ColorDiff : null
+}
+
+export function expectColorFile(): typeof ColorFile | null {
+  return getColorModuleUnavailableReason() === null ? ColorFile : null
+}
+
+export function getSyntaxTheme(themeName: string): SyntaxTheme | null {
+  return getColorModuleUnavailableReason() === null
+    ? nativeGetSyntaxTheme(themeName)
+    : null
+}