v0.8.0: export a playlist — as a folder, or as a whole website

File → Export Playlist…, and the same item on a playlist's right-click
menu. A sibling of device_sync: pure plan_export() first, then a worker
on a daemon thread sharing the status-bar progress widgets. The manifest
(index.html / .m3u) is written last, so an interrupted export never
leaves a page naming files that aren't there.

Two destinations. A folder gives the audio under "Artist - Title" names
plus an extended .m3u. A web mix gives a self-contained static site
reproducing the hand-made yearly mixes, with a dialog for title,
description and hero image.

audio.js and jQuery are gone. The old pages shipped ~293 KB: a build of
audio.js whose upstream hasn't moved since 2012, plus jQuery 3.2.1
(CVE-2019-11358, CVE-2020-11022, CVE-2020-11023 — unexploitable on a
static page, since nothing untrusted reaches a jQuery HTML sink, but
dead weight regardless). audio.js never used jQuery; jQuery was there
for ~25 lines of tracklist glue. Both are replaced by a dependency-free
player.js plus a player.css transcribed from the customized audio.js
skin, so the page looks identical — same 250px #c7b563 bar, same
player-graphics.gif (byte-identical: it's an animated GIF whose loading
frame is a spinner), same shortcuts. ~293 KB → ~6 KB. The Flash
fallback went too; audio.js gated it on !canPlayType("audio/mpeg;"),
unreachable since ~2010.

Conversion happens only when a browser genuinely can't decode a file,
never because of bitrate — a 320 kbps MP3 is copied verbatim. Everything
that does convert targets FLAC, so a conversion cannot cost a bit; a
test asserts the exported FLAC's decoded PCM hashes identical to the
ALAC source. Against the real library that's 105 Apple Lossless and 8
AIFF out of 21,382 tracks. DRM'd tracks are reported in a confirmation
dialog, never silently dropped and never attempted. ffmpeg is the CLI
binary here, not Qt's ffmpeg backend, so it's detected at runtime.

Verified in Chromium 151 and Firefox 153 over CDP/Marionette: every
exported format decodes including the converted FLAC, the player builds,
click / space / arrows / scrubber-seek / autoplay-next all work, and the
network log shows no request for jquery, audio.min.js or any .swf.

mix-example/ removed; the template reproduces it.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

setup.py

@@ -12,6 +12,9 @@ setup(
     name="lintunes",
     version=_version,
     packages=find_packages(),
+    # The web-mix templates (player.js/css, the player sprite GIF and
+    # the placeholder image) must ride along in an installed copy.
+    package_data={"lintunes.export": ["templates/*"]},
     install_requires=[
         "PyQt6>=6.8.0",  # QAudioBufferOutput (visualizer) needs Qt 6.8+
         "mutagen>=1.46",