Live: polling rework, source locks, preflight scaffolding, Vue previews

Carved out of #371, minus progressive publication. Everything here works
against real project source the way main's Live already does: the agent
writes variants into the file the browser loaded, HMR fires, Accept
promotes and carbonizes. Nothing is staged anywhere.

Poll lanes. Events now carry an explicit priority: accept/discard/exit
ahead of manual_edit_apply/steer/carbonize_cleanup ahead of generate. A
long generate can no longer sit in front of the Accept the user just
clicked. leaseEvent claims its lease before awaiting, so a slow prepare
cannot hand the same event to two pollers.

Source locks. A per-file mutex around every accept and discard path, keyed
on a digest of the absolute path. Staleness is decided by owner-pid
liveness rather than mtime, so a wedged lock clears when its owner dies
instead of after an arbitrary timeout, and a slow-but-live accept is never
stolen from. Only the owning process can release a lock.

Preflight scaffolding. The server runs live-wrap (or live-insert) before
the poll returns and hands the result back as event.scaffold. That walk is
measured at ~7.6s on a large repo; moving it off the agent's critical path
removes a deterministic tool round trip without touching the generated
design. Falls back cleanly to the agent running the helper itself.

Vue previews. previewMode: "vue-component" for Nuxt/Vue targets, matching
the existing Svelte component path: variants compile as real SFCs from a
dev-only directory so the route is never rewritten during generation, and
Vite mounts them without invalidating page state. Accept is the only route
write. Includes a Vue attr tokenizer that normalizes shorthand bindings
(@x, :x, #x) to their canonical forms.

Accept hardening. Every thrown failure now returns mode: 'error' rather
than an ambiguous unhandled result, so a real failure is never classified
as a deliberate manual handoff and silently dropped. The marker search
skips node_modules/.git/dist/build/.impeccable.

Shared CLI arg parsing extracted to scripts/lib/cli-args.mjs.

Assisted-by: Claude Code

skill/scripts/hook-lib.mjs

@@ -502,15 +502,12 @@ export function normalizeIgnoreValueEntries(entries) {
       ...(Array.isArray(entry.files) ? entry.files.filter(v => typeof v === 'string' && v.trim()).map(v => v.trim()) : []),
     ]);
     if (files.length > 0) normalized.files = files;
-    // Key order is rule, value, files, createdAt, reason and must stay that way:
-    // normalizing runs on every write, so emitting a different order than the one
-    // already on disk rewrites every untouched entry and churns the diff.
-    if (typeof entry.createdAt === 'string' && entry.createdAt.trim()) {
-      normalized.createdAt = entry.createdAt.trim();
-    }
     if (typeof entry.reason === 'string' && entry.reason.trim()) {
       normalized.reason = entry.reason.trim();
     }
+    if (typeof entry.createdAt === 'string' && entry.createdAt.trim()) {
+      normalized.createdAt = entry.createdAt.trim();
+    }
     out.push(normalized);
   }
   return out;
@@ -1468,17 +1465,16 @@ export function appendDesignSystemNote(text, scanOptions) {
 //      raw envelope. Asking the model to surface the resolution in its
 //      reply is the cheapest way to make the feedback loop visible.
 function directiveFooter(display, opts = {}) {
-  // Offer the rule-scoped-to-file form first. `ignore-file` silences every rule
-  // for the path forever, which is far more than one noisy rule on a real UI
-  // surface justifies, and it was previously the only option named here.
-  const target = opts.grouped ? '<path>' : quoteCommandArg(display);
-  const fileIgnoreGuidance = `run \`${IMPECCABLE_COMMAND} hooks ignore-value <id> "*" --file ${target}\` to scope just that rule to the file, or \`${IMPECCABLE_COMMAND} hooks ignore-file ${target}\` only when the whole file is out of scope for design review (a fixture, a generated artifact, a deliberate demo)`;
+  const ignoreFileCommand = `${IMPECCABLE_COMMAND} hooks ignore-file ${quoteCommandArg(display)}`;
+  const fileIgnoreGuidance = opts.grouped
+    ? `run \`${IMPECCABLE_COMMAND} hooks ignore-file <path>\` for the specific file`
+    : `run \`${ignoreFileCommand}\``;
   return [
     'Handle these before finalizing: fix findings that are real design problems, or explicitly classify contextually intentional findings as false positives. Acknowledge what you changed or why you are leaving a finding unchanged.',
     '',
     'Use context judgment before editing. A finding is not automatically a defect; literal or domain-appropriate motion, intentional demos or fixtures, documentation of bad design, and user-confirmed choices can be valid as-is.',
     '',
-    `Do not change intentional design just to satisfy the hook, and do not silence a real finding with an inline ignore comment to skip fixing it. Suppress a finding only after the user explicitly confirms it is intentional. Prefer a config ignore (one reviewable place, the commands below); reach for an inline \`impeccable-disable <rule>\` comment only when the waiver must travel with a file that leaves the repo, such as an exported or standalone document. Prefer the narrowest persisted exception: run the exact \`${IMPECCABLE_COMMAND} hooks ignore-value ... --shared\` command shown next to a value-specific finding. For \`overused-font\`, use \`ignore-value\` for a specific font and use \`${IMPECCABLE_COMMAND} hooks ignore-rule overused-font --all-values\` only when the user asks to ignore overused fonts generally. For a finding whose line shows no exact ignore-value command, such as \`side-tab\`, ${fileIgnoreGuidance}; use \`${IMPECCABLE_COMMAND} hooks ignore-rule <id>\` only when the user asks to suppress the whole non-value-specific rule. Run ${IMPECCABLE_COMMAND} audit for the full pass.`,
+    `Do not change intentional design just to satisfy the hook, and do not silence a real finding with an inline ignore comment to skip fixing it. Suppress a finding only after the user explicitly confirms it is intentional. Prefer a config ignore (one reviewable place, the commands below); reach for an inline \`impeccable-disable <rule>\` comment only when the waiver must travel with a file that leaves the repo, such as an exported or standalone document. Prefer the narrowest persisted exception: run the exact \`${IMPECCABLE_COMMAND} hooks ignore-value ... --shared\` command shown next to a value-specific finding. For \`overused-font\`, use \`ignore-value\` for a specific font and use \`${IMPECCABLE_COMMAND} hooks ignore-rule overused-font --all-values\` only when the user asks to ignore overused fonts generally. For file-specific findings without an ignore-value command, ${fileIgnoreGuidance}; use \`${IMPECCABLE_COMMAND} hooks ignore-rule <id>\` only when the user asks to suppress the whole non-value-specific rule. Run ${IMPECCABLE_COMMAND} audit for the full pass.`,
   ].join('\n');
 }