Record a take from the microphone in the Song tab (#342)

A song could only be filled with sounds that were made somewhere else.
Record plays the song from the cursor and takes the input meanwhile, so
a part played along lands on the bar it was played to.

- An audio worklet takes the input's samples on the clock the song
  plays on. Each run carries the frame it was taken at, so the take is
  cut where the song was heard to start. The output's and the input's
  latency are taken off, as far as the browser reports them.
- The take goes up as mono 16-bit WAV. Sound, a new track "Recording"
  under the track clicked last and the item at the cursor are one undo
  step. The sound is named "Song – Take 1", 2, 3 and so on.
- While recording the take grows red with its waveform on its track,
  and a meter beside the input dropdown shows the level. The lanes take
  no edits then, only a middle-drag pans.
- The loop is not used while recording. The song plays once through
  and on past its end until Stop, Play or Space keep the take. Esc
  throws it away and nothing goes up.
- Echo cancelling, noise suppression and auto gain are off, nothing is
  played back. The input picked is kept in localStorage.
- A take stops by itself at the size a sound may have. A failed upload
  offers Retry, Download WAV and Discard.
- The API takes sounds up to 256 MB and bodies of the same size. nginx
  and PHP were raised to match outside the repo (body 256m, upload and
  post 256M, memory_limit 512M).
- The pure rules (cut, cap, WAV header, name, track) live in
  core/music/take.ts. The scheduler tells where it started on the
  audio clock.
- The e2e browser gets chromium's fake microphone and skips the
  permission prompt. Each run leaves its take in the sound store.

Found on the way:
- The header was too full with the new widgets and cut the track and
  item count on the right. Input dropdown and meter are narrower now.

Tests:
- Unit take.test.ts: 7 new, svg-icons adjusted to 8 toolbar icons
- e2e 65 (melektaus-atx): ALL PASSED – 31 checks (+4)
- Gate (melektaus-atx): CHECK EXIT 0, 252 files, 3923 tests
- Probe on stein2: a 3 s take of the test tone, peak 32767,
  285100 bytes, waveform seen in the screenshot

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

api/index.php

@@ -93,7 +93,7 @@ require __DIR__ . '/lib/TextureStore.php';
 require __DIR__ . '/lib/UserStore.php';
 
 /** Has to clear the largest single upload below, which is a sound; the web server has its own say. */
-const MAX_BODY_BYTES = 20 * 1024 * 1024;
+const MAX_BODY_BYTES = 256 * 1024 * 1024;
 
 /** Upload ceiling for a single image. The editor downscales larger pictures before sending. */
 const MAX_TEXTURE_BYTES = 4 * 1024 * 1024;
@@ -101,8 +101,8 @@ const MAX_TEXTURE_BYTES = 4 * 1024 * 1024;
 /** Upload ceiling for a single font. A font cannot be shrunk on the way, so this is a plain limit. */
 const MAX_FONT_BYTES = 4 * 1024 * 1024;
 
-/** The same for a sound, four times as high: one music track is worth more than four typefaces. */
-const MAX_SOUND_BYTES = 16 * 1024 * 1024;
+/** The same for a sound, far higher: a recorded take is plain WAV, about 46 minutes in mono. */
+const MAX_SOUND_BYTES = 256 * 1024 * 1024;
 
 set_error_handler(static function (int $severity, string $message, string $file, int $line): bool {
     // PHP calls the handler for a call silenced with `@` as well, only with less reported: that