Fix Live accept for Elixir templates in lib/ (#374)

* Fix Live accept for Elixir templates in lib/

Wrap and accept search the repo for impeccable variant markers. That
search skipped .ex files and the lib/ tree, so Phoenix LiveView markup
inside ~H""" blocks never matched and browser Accept returned
"Session markers not found".

Extend the same EXTENSIONS and searchDirs in live-accept.mjs and
live-wrap.mjs. Add a regression test that accepts from
lib/my_app_web/components/layouts.ex.

* Live: give the source search one owner for template extensions

The #374 fix had to patch the same hardcoded EXTENSIONS array in two
files because live-wrap.mjs and live-accept.mjs each carried their own
copy of the project source walk. The copies had already drifted: same
extension list twice, same searchDirs twice, and one realpathSync
guarded by try/catch while the other was not.

Meanwhile hook-lib.mjs had solved this properly for the design hook in
#316/#347 with a configurable `detector.extensions` and suffix matching
that handles .blade.php and .html.erb. Live never read it, so a project
that taught the hook about .heex still got 'Session markers not found'
on Accept.

- lib/template-extensions.mjs is the single owner. It holds Live's
  built-in markup list, the suffix matcher, and the detector.extensions
  config reader. hook-lib.mjs now imports its normalize/merge/match
  helpers from here instead of duplicating them, and re-exports
  matchConfiguredExtension for its existing callers.
- Live resolves built-ins PLUS detector.extensions, so teaching the hook
  about a server template teaches wrap and accept at the same time.
- live/source-search.mjs holds the walk both scripts share. Callers pass
  the one thing that actually differs (skipDirs, fileFilter). Unifying
  gives live-wrap the guarded realpathSync, so a dangling symlink in the
  tree no longer throws out of the whole wrap, and makes it skip
  .impeccable artifacts the way accept already did.
- Extensions are matched on filename suffix rather than path.extname, so
  root.html.heex and show.html.erb resolve.
- Drop .exs. Those are Elixir scripts (mix.exs, config/*.exs), never
  markup, and including them only lets a wrap query match build config.
- Fill the Elixir gap in the manual-edit paths, which kept their own
  allowlists and would have left Live half-working for Phoenix:
  live-commit-manual-edits.mjs and live-manual-edit-evidence.mjs.

Verified the round trip by hand against a Phoenix layout: wrap injects
markers into a ~H""" block in lib/**/*.ex, accept carbonizes the chosen
variant back out.

AI assistance: written with Claude Code.

Co-Authored-By: Claude <noreply@anthropic.com>

---------

Co-authored-by: Nils Kanevad <heliumbrain@users.noreply.github.com>
Co-authored-by: Paul Bakaus <paul.bakaus@gmail.com>
Co-authored-by: Claude <noreply@anthropic.com>

skill/scripts/live-accept.mjs

@@ -16,8 +16,10 @@
 import fs from 'node:fs';
 import path from 'node:path';
 import { isGeneratedFile } from './lib/is-generated.mjs';
-import { IMPECCABLE_DIR, getLiveDir, safeSessionId } from './lib/impeccable-paths.mjs';
+import { getLiveDir, safeSessionId } from './lib/impeccable-paths.mjs';
+import { resolveLiveTemplateExtensions } from './lib/template-extensions.mjs';
 import { readBuffer as readManualEditsBuffer, writeBuffer as writeManualEditsBuffer } from './live/manual-edits-buffer.mjs';
+import { NEVER_SOURCE_DIRS, findSourceFile } from './live/source-search.mjs';
 import { withSourceLockSync } from './live/source-lock.mjs';
 import {
   applyDeferredSvelteComponentAccepts,
@@ -26,7 +28,6 @@ import {
   removeSvelteComponentSession,
 } from './live/svelte-component.mjs';
 
-const EXTENSIONS = ['.html', '.jsx', '.tsx', '.vue', '.svelte', '.astro'];
 const ACCEPT_LOCK_WAIT_MS = 1_000;
 // Mirrors VARIANT_ID_PATTERN in live/event-validation.mjs, which gates the same
 // value arriving over HTTP.
@@ -892,66 +893,23 @@ function detectCommentSyntax(filePath) {
 // ---------------------------------------------------------------------------
 
 /**
- * `.impeccable` is the critical entry, and it is not cosmetic.
- *
- * Progressive publication stages each revision as `.impeccable/live/artifacts/
- * <id>-r<n>.<source-ext>`, and those artifacts carry the very marker this search
- * looks for. The walk reaches `.` for any project whose source is not under one
- * of the privileged dirs above (this repo's own site lives in `site/pages/`), and
- * dot-directories sort before letters, so the artifact was found *before* the
- * real file. isGeneratedFile then declined the accept, and the agent fell back to
- * carbonizing several hundred lines of stylesheet by hand.
- *
- * Impeccable's own state directory is never project source. Never search it.
+ * Accept also skips `dist` / `build` outright, where wrap descends into them so
+ * its `includeGenerated` second pass can report a `generatedMatch`. Accept has
+ * no such pass: a marker found in build output is only ever a stale copy of the
+ * marker in source.
  */
-const SEARCH_SKIP_DIRS = new Set(['node_modules', '.git', 'dist', 'build', IMPECCABLE_DIR]);
+const SEARCH_SKIP_DIRS = [...NEVER_SOURCE_DIRS, 'dist', 'build'];
 
 function findSessionFile(id, cwd) {
-  const marker = 'impeccable-variants-start ' + id;
-  const searchDirs = ['src', 'app', 'pages', 'components', 'public', 'views', 'templates', '.'];
-  const seen = new Set();
-
-  for (const dir of searchDirs) {
-    const absDir = path.join(cwd, dir);
-    if (!fs.existsSync(absDir)) continue;
-    const result = searchDir(absDir, marker, seen, 0);
-    if (result) {
-      const content = fs.readFileSync(result, 'utf-8');
-      return { file: result, content, lines: content.split('\n') };
-    }
-  }
-  return null;
-}
-
-function searchDir(dir, query, seen, depth) {
-  if (depth > 5) return null;
-  let realDir;
-  try { realDir = fs.realpathSync(dir); } catch { return null; }
-  if (seen.has(realDir)) return null;
-  seen.add(realDir);
-
-  let entries;
-  try { entries = fs.readdirSync(dir, { withFileTypes: true }); }
-  catch { return null; }
-
-  for (const entry of entries) {
-    if (!entry.isFile()) continue;
-    if (!EXTENSIONS.includes(path.extname(entry.name).toLowerCase())) continue;
-    const filePath = path.join(dir, entry.name);
-    try {
-      const content = fs.readFileSync(filePath, 'utf-8');
-      if (content.includes(query)) return filePath;
-    } catch { /* skip */ }
-  }
-
-  for (const entry of entries) {
-    if (!entry.isDirectory()) continue;
-    if (SEARCH_SKIP_DIRS.has(entry.name)) continue;
-    const result = searchDir(path.join(dir, entry.name), query, seen, depth + 1);
-    if (result) return result;
-  }
-
-  return null;
+  const result = findSourceFile({
+    query: 'impeccable-variants-start ' + id,
+    cwd,
+    extensions: resolveLiveTemplateExtensions(cwd),
+    skipDirs: SEARCH_SKIP_DIRS,
+  });
+  if (!result) return null;
+  const content = fs.readFileSync(result, 'utf-8');
+  return { file: result, content, lines: content.split('\n') };
 }
 
 // ---------------------------------------------------------------------------