diff --git a/config/scripts/renderer-boot-graph.mjs b/config/scripts/renderer-boot-graph.mjs
index a0168cb8f1b..d99c5468e78 100644
--- a/config/scripts/renderer-boot-graph.mjs
+++ b/config/scripts/renderer-boot-graph.mjs
@@ -84,6 +84,13 @@ export function findForbiddenBootPayloads(rendererDir, payloads) {
   return violations
 }
 
+// V8 keeps a whole script as UTF-16 when any char is above U+00FF, doubling that boot chunk's memory.
+export function findTwoByteBootChunks(rendererDir) {
+  return readRendererBootGraph(rendererDir)
+    .chunks.filter((chunk) => /[\u0100-\uffff]/.test(fs.readFileSync(chunk.file, 'utf8')))
+    .map((chunk) => path.basename(chunk.file))
+}
+
 export function verifyRendererBootGraph(root = process.cwd()) {
   const rendererDir = path.join(root, RENDERER_BUILD_DIR)
   const { chunks, totalBytes } = readRendererBootGraph(rendererDir)
@@ -91,6 +98,15 @@ export function verifyRendererBootGraph(root = process.cwd()) {
   console.log(
     `Renderer boot graph: ${chunks.length} chunks, ${(totalBytes / 1024).toFixed(1)} KB minified.`
   )
+  const twoByteChunks = findTwoByteBootChunks(rendererDir)
+  if (twoByteChunks.length > 0) {
+    console.error('Boot chunks contain chars above U+00FF that output.charset cannot escape:')
+    for (const chunk of twoByteChunks) {
+      console.error(`  ${chunk}`)
+    }
+    console.error('Escape them in the source (e.g. \\u2014 inside String.raw regex sources).')
+    return 1
+  }
   if (violations.length === 0) {
     return 0
   }
diff --git a/electron.vite.config.ts b/electron.vite.config.ts
index 5c5f98f9322..98bb16bd983 100644
--- a/electron.vite.config.ts
+++ b/electron.vite.config.ts
@@ -227,6 +227,8 @@ export const electronViteConfig: UserConfig = {
         preserveEntrySignatures: 'exports-only',
         // Electron and sidecar launchers require stable CommonJS paths despite Rolldown’s SSR ESM default.
         output: {
+          // V8 stores a whole script as UTF-16 when any char is above U+00FF; escaping keeps sources one-byte (half the memory).
+          charset: 'ascii',
           format: 'cjs',
           entryFileNames: '[name].js',
           chunkFileNames: 'chunks/[name]-[hash].js'
@@ -260,6 +262,10 @@ export const electronViteConfig: UserConfig = {
     build: {
       externalizeDeps: {
         exclude: ['zod']
+      },
+      rollupOptions: {
+        // Unminified preload keeps dependency JSDoc whose em dashes would force two-byte storage in every renderer.
+        output: { charset: 'ascii', comments: { legal: true, annotation: true, jsdoc: false } }
       }
     }
   },
@@ -284,7 +290,10 @@ export const electronViteConfig: UserConfig = {
       createViteCacheRetentionPlugin()
     ],
     worker: {
-      format: 'es'
+      format: 'es',
+      rollupOptions: {
+        output: { charset: 'ascii' }
+      }
     },
     build: {
       manifest: true,
@@ -296,6 +305,7 @@ export const electronViteConfig: UserConfig = {
       rollupOptions: {
         // Shared chunks must not import HTML entries that mount another React root.
         preserveEntrySignatures: 'strict',
+        output: { charset: 'ascii' },
         input: {
           index: resolve('src/renderer/index.html'),
           popout: resolve('src/renderer/popout.html'),
diff --git a/src/shared/prose-url-boundary.ts b/src/shared/prose-url-boundary.ts
index 0f12c31bdf6..f7071462576 100644
--- a/src/shared/prose-url-boundary.ts
+++ b/src/shared/prose-url-boundary.ts
@@ -1,6 +1,7 @@
 // Why not all non-ascii punctuation: titles keep `・`, `–` and `·` unencoded in a url
 // (`/wiki/ジョン・スミス`), so only brackets, quotes, spaces and sentence marks end one.
-const PROSE_URL_TERMINATOR_SOURCE = String.raw`(?![\0-\x7f])[\p{Ps}\p{Pe}\p{Pi}\p{Pf}\p{Z}、。，．！？：；｡､…‥—]`
+// Escaped CJK sentence marks 、。，．！？：；｡､…‥— keep this module's chunk one-byte in V8.
+const PROSE_URL_TERMINATOR_SOURCE = String.raw`(?![\0-\x7f])[\p{Ps}\p{Pe}\p{Pi}\p{Pf}\p{Z}\u3001\u3002\uFF0C\uFF0E\uFF01\uFF1F\uFF1A\uFF1B\uFF61\uFF64\u2026\u2025\u2014]`
 
 const NOT_PROSE_URL_TERMINATOR = `(?!${PROSE_URL_TERMINATOR_SOURCE})`