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/reference/hooks.md

@@ -23,11 +23,10 @@ The first argument is the action. Defaults to `status`.
 | `status` | Print current state, shared/local config paths, ignored rules / files / values, env override. |
 | `on` | Set `enabled: true` in `.impeccable/config.json`, record local hook consent as accepted, and install/repair provider hook manifests when the skill is installed. |
 | `off` | Set `enabled: false` in `.impeccable/config.json`. |
-| `ignore-rule <id>` | Append `<id>` to `detector.ignoreRules`; for `overused-font`, requires `--all-values`. Suppresses the rule across the whole project. |
-| `ignore-file <glob>` | Append `<glob>` to `detector.ignoreFiles`. Suppresses **every** rule for matching files. |
+| `ignore-rule <id>` | Append `<id>` to `detector.ignoreRules`; for `overused-font`, requires `--all-values`. |
+| `ignore-file <glob>` | Append `<glob>` to `detector.ignoreFiles`. |
 | `ignore-value <id> <value> [--shared] [--reason "..."]` | Append a rule/value suppression to shared `.impeccable/config.json`. |
 | `ignore-value <id> <value> --local [--reason "..."]` | Append a private rule/value suppression to `.impeccable/config.local.json`. |
-| `ignore-value <id> "*" --file <glob> [--file <glob>...]` | Turn one rule off in matching files only, leaving it active everywhere else. Repeat `--file`, or use `--file=<glob>` / `--files=<glob>`. A bare `"*"` with no `--file` is refused: use `ignore-rule <id>` if you really mean project-wide. |
 | `reset` | Delete the project config, dedup cache, and Cursor pending queue. |
 
 ## Flow
@@ -52,8 +51,7 @@ Prefer the narrowest exception:
 
 - If the finding line shows an exact `ignore-value` command, run that command. This writes shared `.impeccable/config.json` by default.
 - For value-specific findings such as `overused-font` and `bounce-easing`, use `ignore-value` when the user confirms the specific value. Do not use `ignore-rule overused-font` for a specific font.
-- If the finding has no value-specific command, such as `side-tab`, scope that one rule to the file: `ignore-value <id> "*" --file <path>`. Run `npx impeccable detect <path>` first to see what actually fires there.
-- Reach for `ignore-file <path>` only when the whole file is out of scope for design review: a fixture, a generated artifact, a deliberate slop demo. It silences every rule for that file permanently, including rules that have not been written yet. A real UI surface with one noisy rule wants the file-scoped value ignore above.
+- If the finding has no value-specific command, such as `side-tab`, prefer `ignore-file <path>` for the current file.
 - Use `ignore-rule <id>` only when the user asks to suppress that whole rule across the project. For broad overused-font suppression, use `ignore-rule overused-font --all-values` only when the user asks to ignore overused fonts generally.
 - Prefer config ignores (the commands above) by default; they keep suppressions in one reviewable place. Reach for an inline comment only when the waiver must travel with a single file that leaves the repo (a generated/exported standalone document, an emailed HTML file). The supported marker is `impeccable-disable <rule>` (whole file) or `impeccable-disable-line` / `impeccable-disable-next-line` (one line), in any comment syntax, with an optional reason after `:` or `--`. The detector honors it by default; `--no-inline-ignores` or `--no-config` bypasses it.
 
@@ -75,14 +73,7 @@ Example whole-rule font exception:
 node {{scripts_path}}/hook-admin.mjs ignore-rule overused-font --all-values --reason "User asked to ignore overused fonts generally"
 ```
 
-Example one-rule-in-one-file exception, for a file that is still worth reviewing
-for everything else:
-
-```bash
-node {{scripts_path}}/hook-admin.mjs ignore-value design-system-font-size "*" --file "src/overlay/widget.js" --reason "Injected widget builds its own type scale; DESIGN.md's ramp describes the site"
-```
-
-Example whole-file exception, for a file that is out of scope entirely:
+Example file-scoped exception:
 
 ```bash
 node {{scripts_path}}/hook-admin.mjs ignore-file "src/legacy/Card.tsx"