Preserve experimental Live app-server workstream

Snapshot the current app-server implementation, shared Live optimizations, generated harness output, and in-progress site work before restoring polling as the primary runtime path.

Prepared with Codex assistance under maintainer direction.

skill/scripts/live-accept.mjs

@@ -30,6 +30,10 @@ import {
   inlineVueComponentAccept,
   retireVueComponentSession,
 } from './live/vue-component.mjs';
+import {
+  findSourceArtifactManifest,
+  removeSourceArtifactSession,
+} from './live/source-artifact.mjs';
 
 const EXTENSIONS = ['.html', '.jsx', '.tsx', '.vue', '.svelte', '.astro'];
 const ACCEPT_LOCK_WAIT_MS = 1_000;
@@ -106,15 +110,60 @@ Output (JSON):
   }
 
   // Find the file containing this session's markers
-  const found = findSessionFile(id, process.cwd());
+  const sourceArtifactManifest = findSourceArtifactManifest(id, process.cwd());
+  const found = sourceArtifactManifest ? null : findSessionFile(id, process.cwd());
   const svelteComponentManifest = found ? null : findSvelteComponentManifest(id, process.cwd());
   const vueComponentManifest = found || svelteComponentManifest ? null : findVueComponentManifest(id, process.cwd());
 
-  if (!found && !svelteComponentManifest && !vueComponentManifest) {
+  if (!found && !sourceArtifactManifest && !svelteComponentManifest && !vueComponentManifest) {
     console.log(JSON.stringify({ handled: false, error: 'Session markers not found for id: ' + id }));
     process.exit(0);
   }
 
+  if (sourceArtifactManifest) {
+    if (isDiscard) {
+      removeSourceArtifactSession(id, process.cwd());
+      emitResult({
+        handled: true,
+        file: sourceArtifactManifest.sourceFile,
+        sourceFile: sourceArtifactManifest.sourceFile,
+        previewMode: sourceArtifactManifest.previewMode,
+        carbonize: false,
+      });
+      return;
+    }
+
+    let result;
+    try {
+      result = withSourceLockSync(
+        sourceArtifactManifest.sourcePath,
+        'accept:' + id,
+        () => acceptSourceArtifact(sourceArtifactManifest, variantNum, paramValues),
+        { waitMs: ACCEPT_LOCK_WAIT_MS },
+      );
+    } catch (err) {
+      result = { handled: false, error: err.message };
+    }
+    if (result.handled !== false) {
+      removeSourceArtifactSession(id, process.cwd());
+      try {
+        scrubManualEditsAgainstOriginalBlock(result.acceptedOriginalText || '', process.cwd(), pageUrl);
+      } catch {}
+    }
+    delete result.acceptedOriginalText;
+    if (result.carbonize) {
+      result.todo = 'REQUIRED before next poll: carbonize cleanup in ' + sourceArtifactManifest.sourceFile + '. See reference/live.md "Required after accept".';
+    }
+    emitResult({
+      handled: result.handled !== false,
+      file: sourceArtifactManifest.sourceFile,
+      sourceFile: sourceArtifactManifest.sourceFile,
+      previewMode: sourceArtifactManifest.previewMode,
+      ...result,
+    });
+    return;
+  }
+
   if (vueComponentManifest) {
     if (isDiscard) {
       let result;
@@ -447,6 +496,16 @@ function handleAccept(id, variantNum, _lines, targetFile, paramValues) {
 }
 
 function handleAcceptUnlocked(id, variantNum, lines, targetFile, paramValues) {
+  const built = buildAcceptedWrappedSource(id, variantNum, lines, targetFile, paramValues);
+  if (built.handled === false) return built;
+  fs.writeFileSync(targetFile, built.content, 'utf-8');
+  return {
+    carbonize: built.carbonize,
+    acceptedOriginalText: built.acceptedOriginalText,
+  };
+}
+
+function buildAcceptedWrappedSource(id, variantNum, lines, targetFile, paramValues) {
   const block = findMarkerBlock(id, lines);
   if (!block) return { handled: false, error: 'Markers not found' };
 
@@ -491,9 +550,38 @@ function handleAcceptUnlocked(id, variantNum, lines, targetFile, paramValues) {
     ...replacement,
     ...lines.slice(replaceRange.end + 1),
   ];
-  fs.writeFileSync(targetFile, newLines.join('\n'), 'utf-8');
+  return {
+    content: newLines.join('\n'),
+    carbonize: needsCarbonize,
+    acceptedOriginalText: originalContent.join('\n'),
+  };
+}
 
-  return { carbonize: needsCarbonize, acceptedOriginalText: originalContent.join('\n') };
+function acceptSourceArtifact(manifest, variantNum, paramValues) {
+  const source = fs.readFileSync(manifest.sourcePath, 'utf-8');
+  const preview = fs.readFileSync(manifest.previewPath, 'utf-8');
+  const original = String(manifest.originalSource || '');
+  if (!original) return { handled: false, error: 'source_artifact_original_missing' };
+  const first = source.indexOf(original);
+  if (first < 0) return { handled: false, error: 'source_artifact_original_changed' };
+  if (source.indexOf(original, first + original.length) >= 0) {
+    return { handled: false, error: 'source_artifact_original_ambiguous' };
+  }
+  const wrapped = source.slice(0, first) + preview + source.slice(first + original.length);
+  const built = buildAcceptedWrappedSource(
+    manifest.id,
+    variantNum,
+    wrapped.split('\n'),
+    manifest.sourcePath,
+    paramValues,
+  );
+  if (built.handled === false) return built;
+  fs.writeFileSync(manifest.sourcePath, built.content, 'utf-8');
+  return {
+    handled: true,
+    carbonize: built.carbonize,
+    acceptedOriginalText: built.acceptedOriginalText,
+  };
 }
 
 function readSourceShadowPreviewMeta(content, id) {