Upload date in UI; extract HTML_UI; Twitch clips mode; DB connection pool

Four nice-to-have items, plus surfacing the upload date in both UIs
since the user explicitly asked.

Upload date display
- Desktop: card meta row now includes a `YYYY-MM-DD` cell between the
  ID and the duration; detail panel header shows it as `📅 YYYY-MM-DD`.
- Web: video player modal title gains a date+duration subline so the
  viewer has context without opening the metadata pane (card meta
  already shows the date).
- New `format_upload_date()` helper on the desktop side; the web side
  reuses the existing `fmtDate()` JS.

Extract HTML_UI to include_str!
- `LOGIN_HTML` and `HTML_UI` moved out of `src/web.rs` into
  `src/web_ui/login.html` and `src/web_ui/index.html`. The Rust file
  drops from 2915 lines to 1806; editors now syntax-highlight the
  HTML/CSS/JS, and UI diffs no longer overwhelm the Rust diff view.
- `include_str!` bakes them into the binary at compile time, so there
  is no runtime fs lookup and no extra deploy artifacts.

Twitch clips-only mode
- `classify_twitch` now recognises `twitch.tv/<user>/clips` as a
  Channel URL (was Unknown), so yt-dlp's TwitchClips extractor is
  reachable from our normal download pipeline.
- Both UIs gain a "Clips only" toggle visible only when the URL is
  a Twitch channel (not a specific VOD/clip). On submit, the URL is
  rewritten to `twitch.tv/<user>/clips` before dispatch.
- 1 new platform test covers the clips-listing classification.

DB connection pool (r2d2_sqlite)
- `Database` now wraps an `r2d2`-managed SQLite pool. File-backed
  databases get up to 4 connections; the in-memory fallback is capped
  at 1 (since each in-memory connection is a fresh empty DB by default
  in SQLite).
- `WebState.db` drops its outer `Mutex` — concurrent handlers each
  check out their own connection from the pool. Static-file fetches
  through `/files/` no longer serialize on the watched/positions/
  password lookups that the auth middleware performs.
- Pool init failures are converted to `rusqlite::Error` so the
  existing `Result<T>` return types still work.

47 unit tests pass.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/app.rs

@@ -88,6 +88,10 @@ pub struct App {
     dl_music_mode: bool,
     /// Record an ongoing live stream from the start instead of joining live.
     dl_live: bool,
+    /// For Twitch channel URLs: target the `/clips` listing instead of the
+    /// default profile (VODs / past broadcasts). Has no effect on other
+    /// platforms or on single-video URLs.
+    dl_twitch_clips: bool,
     textures: HashMap<PathBuf, Option<egui::TextureHandle>>,
     thumb_request_tx: Sender<PathBuf>,
     thumb_result_rx: Receiver<(PathBuf, Option<egui::ColorImage>)>,
@@ -225,6 +229,7 @@ impl App {
             dl_quality: DownloadQuality::Best,
             dl_music_mode: false,
             dl_live: false,
+            dl_twitch_clips: false,
             textures: HashMap::new(),
             thumb_request_tx,
             thumb_result_rx,
@@ -947,11 +952,32 @@ impl App {
                              so yt-dlp records from the beginning instead of joining mid-stream. \
                              Also waits if the stream hasn't begun yet.",
                         );
+                    if info.platform == Platform::Twitch
+                        && matches!(info.kind, UrlKind::Channel { .. })
+                    {
+                        ui.checkbox(&mut self.dl_twitch_clips, "Clips only (Twitch)")
+                            .on_hover_text(
+                                "Pull only the channel's Clips section instead of the \
+                                 default VOD/highlights mix. Rewrites the URL to \
+                                 twitch.tv/<channel>/clips before submitting.",
+                            );
+                    }
                 }
 
                 let ready = !self.dl_url.trim().is_empty();
                 if ui.add_enabled(ready, egui::Button::new("⬇  Start download")).clicked() {
-                    let url = self.dl_url.trim().to_string();
+                    let mut url = self.dl_url.trim().to_string();
+                    // Twitch clips-only: rewrite `twitch.tv/<user>` to
+                    // `twitch.tv/<user>/clips`. yt-dlp's TwitchClips extractor
+                    // handles the rest and we still classify it as Channel so
+                    // the output folder is unchanged.
+                    if self.dl_twitch_clips
+                        && info.platform == Platform::Twitch
+                        && matches!(info.kind, UrlKind::Channel { .. })
+                        && !url.contains("/clips")
+                    {
+                        url = format!("{}/clips", url.trim_end_matches('/'));
+                    }
                     let dest = dest_preview.clone();
                     if self.dl_music_mode {
                         self.downloader.start_music(url);
@@ -1708,6 +1734,16 @@ impl App {
                 });
 
                 ui.horizontal(|ui| {
+                    if let Some(date) = video.upload_date.as_deref().map(format_upload_date) {
+                        if !date.is_empty() {
+                            ui.label(
+                                egui::RichText::new(format!("📅 {date}"))
+                                    .small()
+                                    .weak(),
+                            );
+                            ui.label(egui::RichText::new("·").weak());
+                        }
+                    }
                     if let Some(secs) = video.duration_secs {
                         ui.label(egui::RichText::new(format_duration(secs)).small().weak());
                         ui.label(egui::RichText::new("·").weak());
@@ -2076,6 +2112,12 @@ impl App {
                                 ui.label(egui::RichText::new("·").weak());
                             }
                             ui.label(egui::RichText::new(&card.id).small().monospace().weak());
+                            if let Some(date) = card.upload_date.as_deref().map(format_upload_date) {
+                                if !date.is_empty() {
+                                    ui.label(egui::RichText::new("·").weak());
+                                    ui.label(egui::RichText::new(date).small().weak());
+                                }
+                            }
                             if let Some(secs) = card.duration_secs {
                                 ui.label(egui::RichText::new("·").weak());
                                 ui.label(egui::RichText::new(format_duration(secs)).small().weak());
@@ -2306,6 +2348,16 @@ fn format_duration(secs: f64) -> String {
     if h > 0 { format!("{h}:{m:02}:{s:02}") } else { format!("{m}:{s:02}") }
 }
 
+/// Convert yt-dlp's native `YYYYMMDD` upload-date string into `YYYY-MM-DD`
+/// for display. Returns an empty string when input doesn't look like a date
+/// so callers can decide whether to skip the row entirely.
+fn format_upload_date(yyyymmdd: &str) -> String {
+    if yyyymmdd.len() < 8 || !yyyymmdd.chars().all(|c| c.is_ascii_digit()) {
+        return String::new();
+    }
+    format!("{}-{}-{}", &yyyymmdd[..4], &yyyymmdd[4..6], &yyyymmdd[6..8])
+}
+
 fn format_size(bytes: u64) -> String {
     if bytes >= 1_073_741_824 {
         format!("{:.1} GB", bytes as f64 / 1_073_741_824.0)