refactor(renderer): L132 — share resetForm() across download + addPlaylist

Extract the post-enqueue reset (URL + probe + one-shot trim/schedule/advanced/
incognito/options) into resetForm(), called by both download() and addPlaylist().
clearProbe() stays the lighter probe-only reset for onUrlChange. Also fixes a
latent inconsistency: addPlaylist previously left the trim/schedule/advanced
panels open after enqueuing a playlist.

typecheck + eslint + prettier green.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

CODE-AUDIT.md

@@ -770,7 +770,12 @@ token system + shared primitives (UI/SIMP — high value, larger effort) · i18n
   "interrupted"); user-facing ones are capitalized with periods. Fine when interpolated, jarring if shown raw.
 - [ ] **L131 — Taskbar `error` state is ephemeral** — it's driven by live `error` items, so "Clear
   finished" flips the red taskbar bar back to normal even though failures occurred (out of sync with the persisted error log).
-- [ ] **L132 — `clearProbe` + form-reset logic is duplicated** in DownloadBar (`onUrlChange`, `download`, `addPlaylist`).
+- [x] **L132 — `clearProbe` + form-reset logic is duplicated** in DownloadBar (`onUrlChange`, `download`, `addPlaylist`).
+  *Fixed: a shared `resetForm()` in [useDownloadBar.ts](src/renderer/src/components/downloadBar/useDownloadBar.ts)
+  now owns the post-enqueue reset (URL + probe + the one-shot trim/schedule/advanced/incognito/options),
+  called by both `download()` and `addPlaylist()`. `clearProbe()` stays the lighter probe-only reset for
+  `onUrlChange`. Also fixes a latent inconsistency — `addPlaylist` previously left the trim/schedule/advanced
+  panels open after enqueuing.*
 - [ ] **L133 — `Field` controls mix `aria-label` + visible `label`.** Many `Field label="X"` wrap a
   `Select aria-label="X"`, so AT announces the name twice (extends M20 across DownloadOptionsForm).
 - [ ] **L134 — Inconsistent disabled affordance for busy buttons.** Some stay enabled-looking with a