feat(web): summarization-mode UI — all-videos list, Summarize queue, mode toggle

The list now shows ALL videos (ListVideos), not just summaries. Summarized cards
are unchanged; discovered-but-unsummarized videos render with a muted "pending"
treatment and either a "Summarize" button or a "Queued" chip.

- POST /v/{videoId}/summarize queues a video (RequestSummarize) and returns the
  refreshed card — it does NOT run the engine inline; `tapir run` is the single
  summarization driver, which picks up the flag on its next pass.
- Account page gains an Automatic/Manual toggle (POST /account/summarize-mode →
  SetAutoSummarize), shown as the current mode with a one-click switch.
- Both new POSTs degrade without JS (redirect back); HTMX swaps the fragment.

VideoCard and summarizeModeControl are extracted templ fragments reused as the
HTMX swap targets. views_templ.go regenerated.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

internal/web/view.go

@@ -171,6 +171,36 @@ func actionURL(videoID string) templ.SafeURL {
 	return templ.SafeURL("/v/" + videoID + "/action")
 }
 
+// summarizeURL builds the manual-queue POST path for a video id.
+func summarizeURL(videoID string) templ.SafeURL {
+	return templ.SafeURL("/v/" + videoID + "/summarize")
+}
+
+// summarizeModeLabel names the current mode for display.
+func summarizeModeLabel(auto bool) string {
+	if auto {
+		return "Automatic"
+	}
+	return "Manual"
+}
+
+// summarizeModeToggleLabel is the caption on the toggle button — it names the mode
+// the click switches TO (the opposite of the current one).
+func summarizeModeToggleLabel(auto bool) string {
+	if auto {
+		return "Switch to manual"
+	}
+	return "Switch to automatic"
+}
+
+// boolStr renders a bool as the "enabled" form value the toggle submits.
+func boolStr(b bool) string {
+	if b {
+		return "true"
+	}
+	return "false"
+}
+
 // externalURL passes a stored source URL through templ's URL sanitiser.
 func externalURL(u string) templ.SafeURL {
 	return templ.URL(u)
@@ -347,6 +377,15 @@ main { max-width: 60rem; margin: 0 auto; padding: var(--s4) var(--s3); }
 .card-state { color: var(--muted); font-size: .8rem; }
 .badge { display: inline-block; padding: .15rem .55rem; border-radius: 999px; background: var(--badge-bg); color: var(--badge-fg); font-size: .72rem; font-weight: 600; }
 
+/* pending (discovered-but-unsummarized) card: muted until summarized */
+.card-pending { border-style: dashed; }
+.card-pending .card-title { color: var(--muted); font-weight: 600; }
+
+/* summarization mode toggle on the account page */
+.summarize-mode { display: flex; gap: var(--s3); align-items: center; flex-wrap: wrap; }
+.summarize-mode p { margin: 0; }
+.summarize-mode form { margin: 0; }
+
 /* empty state */
 .empty { text-align: center; color: var(--muted); padding: var(--s5) var(--s4); border: 1px dashed var(--line); border-radius: var(--radius); background: var(--card); }
 .empty strong { display: block; color: var(--fg); font-size: 1.05rem; margin-bottom: var(--s2); }