Initial implementation of youtube-automate

A DVR for YouTube subscriptions, laid out so Jellyfin presents each channel
as a show and each video as an episode. Cron-driven, idempotent, with a
public admin UI for a non-operator.

Verified end to end on susan against three real channels: PO tokens, h264
downloads, Jellyfin resolution from local NFOs with all providers disabled,
retention and tombstones.

Corrections to the original design handover (specs.md documents each with
the evidence, and specs.handover-original.md preserves the original):

- The format sort selected 360p. Ranking acodec above res makes `bv*` prefer
  the combined 360p stream, which carries AAC, over the 720p video-only
  stream whose acodec is none. vcodec now leads, so a video without h264 at
  720p yields h264 lower down rather than VP9 this hardware cannot transcode.
- yt-dlp now requires a JS runtime and the yt-dlp-ejs solver scripts, which
  only ship with the [default] extra. Without them the n challenge fails and
  the mweb formats disappear entirely.
- --flat-playlist carries no upload dates, so the specced client-side date
  filter for backfill was impossible. Backfill is RSS-first.
- skipped_old was terminal, so raising a channel's retention appeared to do
  nothing. Added an explicit rescan.
- is_upcoming premieres now defer and retry instead of being skipped forever.
- TubeArchivist is gone, so the media root and the tube.jihakuz.xyz vhost
  were both reclaimed; the latter still pointed at its dead port.

240 offline tests, no network and no real yt-dlp invocation.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

tests/test_nfo.py

@@ -0,0 +1,94 @@
+import xml.etree.ElementTree as ET
+
+from youtube_automate import nfo
+
+HOSTILE = (
+    "Ampersands & angle <brackets> and \"quotes\"\n"
+    "control chars: \x00\x07\x1b\n"
+    "emoji 🎬 and em-dash — and links https://example.com/?a=1&b=2"
+)
+
+
+class TestEpisodeNfo:
+    def build(self, **overrides):
+        kwargs = dict(
+            title="Video Title",
+            show_title="Some Channel",
+            season=2026,
+            episode=8110,
+            plot="A plot.",
+            aired="2026-08-11",
+            duration_seconds=762,
+            video_id="dQw4w9WgXcQ",
+        )
+        kwargs.update(overrides)
+        return nfo.episode_nfo(**kwargs)
+
+    def test_is_well_formed_xml(self):
+        root = ET.fromstring(self.build())
+        assert root.tag == "episodedetails"
+
+    def test_hostile_description_still_parses(self):
+        root = ET.fromstring(self.build(plot=HOSTILE))
+        plot = root.findtext("plot")
+        assert "&" in plot and "<brackets>" in plot
+        assert "🎬" in plot
+
+    def test_control_characters_are_stripped(self):
+        plot = ET.fromstring(self.build(plot=HOSTILE)).findtext("plot")
+        for bad in ("\x00", "\x07", "\x1b"):
+            assert bad not in plot
+
+    def test_newlines_are_preserved(self):
+        plot = ET.fromstring(self.build(plot="one\ntwo")).findtext("plot")
+        assert plot == "one\ntwo"
+
+    def test_runtime_is_rounded_minutes(self):
+        assert ET.fromstring(self.build(duration_seconds=762)).findtext("runtime") == "13"
+
+    def test_short_video_still_gets_at_least_one_minute(self):
+        assert ET.fromstring(self.build(duration_seconds=20)).findtext("runtime") == "1"
+
+    def test_runtime_omitted_when_duration_unknown(self):
+        assert ET.fromstring(self.build(duration_seconds=None)).find("runtime") is None
+
+    def test_unique_id_marks_youtube_as_default(self):
+        unique = ET.fromstring(self.build()).find("uniqueid")
+        assert unique.get("type") == "youtube"
+        assert unique.get("default") == "true"
+        assert unique.text == "dQw4w9WgXcQ"
+
+    def test_season_and_episode_are_present(self):
+        root = ET.fromstring(self.build())
+        assert root.findtext("season") == "2026"
+        assert root.findtext("episode") == "8110"
+
+    def test_title_keeps_characters_that_the_filename_strips(self):
+        root = ET.fromstring(self.build(title="Hermitcraft S11#11: Expanding Business"))
+        assert root.findtext("title") == "Hermitcraft S11#11: Expanding Business"
+
+    def test_empty_plot_does_not_break(self):
+        assert ET.fromstring(self.build(plot=None)).find("plot") is not None
+
+
+class TestTvshowNfo:
+    def test_well_formed_and_carries_channel_id(self):
+        root = ET.fromstring(nfo.tvshow_nfo("clabretro", HOSTILE, "UCabc123"))
+        assert root.tag == "tvshow"
+        assert root.findtext("title") == "clabretro"
+        assert root.findtext("studio") == "YouTube"
+        assert root.find("uniqueid").text == "UCabc123"
+
+
+class TestWrite:
+    def test_write_is_atomic_and_leaves_no_temp_file(self, tmp_path):
+        target = tmp_path / "sub" / "tvshow.nfo"
+        nfo.write(target, b"<tvshow/>")
+        assert target.read_bytes() == b"<tvshow/>"
+        assert list(tmp_path.rglob("*.tmp")) == []
+
+    def test_overwrites_existing(self, tmp_path):
+        target = tmp_path / "tvshow.nfo"
+        nfo.write(target, b"<a/>")
+        nfo.write(target, b"<b/>")
+        assert target.read_bytes() == b"<b/>"