feat(web): unify card states — one 'Summarize now' verb, honest no-captions state

Five explicit footer states, status-primary:
1. Summarized — chip + actions, no button (unchanged)
2. No captions (TranscriptStatus=="none") — NEW: 'No transcript available' muted
   text, no button, no POST URL. Removes the dead-end 'Summarize' button that
   tried and failed when there were no captions to fetch.
3. Queued (SummarizeRequested) — chip + muted text, no button (unchanged)
4. Rate-limited — 'Fetching soon…' + quiet 'Summarize now' → /retry-now
5. Pending — 'Not summarized' + quiet 'Summarize now' → /summarize

One verb ('Summarize now'), one quiet style (.btn-quiet, renamed from .btn-retry
which was state-specific). User doesn't see the internal pipeline distinction;
both buttons post to their existing handlers unchanged. Form class renamed
card-nudge-form. Dropped engineer-facing tooltip; user-facing hint added.
'Try now' wording removed entirely.

internal/web/view.go

@@ -544,9 +544,9 @@ a.btn, a.btn:visited { color: var(--accent-fg); }
 .pipeline-bar { display: flex; gap: var(--s3); align-items: center; flex-wrap: wrap; margin-bottom: var(--s3); font-size: .8rem; color: var(--muted); }
 .pipeline-bar span { display: flex; align-items: center; gap: var(--s1); }
 .pipeline-bar span + span::before { content: "·"; margin-right: var(--s1); }
-.retry-form { display: inline; }
-.btn-retry { font: inherit; font-size: .72rem; font-weight: 600; padding: .15rem .55rem; border-radius: 999px; border: 1px solid var(--accent); background: transparent; color: var(--accent); cursor: pointer; }
-.btn-retry:hover { background: var(--accent-weak); }
+.card-nudge-form { display: inline; }
+.btn-quiet { font: inherit; font-size: .72rem; font-weight: 600; padding: .15rem .55rem; border-radius: 999px; border: 1px solid var(--accent); background: transparent; color: var(--accent); cursor: pointer; }
+.btn-quiet:hover { background: var(--accent-weak); }
 .chip-warn { background: rgba(255, 110, 156, .15); color: #FF6E9C; }
 .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; }