fix(privacy): give training-contribution rows a readable layout (#24)

The opt-in row and its tombstone rendered as one run-on line ('Type 4 ·
brownReceipt contrib-…', 'Withdrawn Oct 21, 12:09 PMraw image, …') because
nothing styled .contribution-row: the label and the receipt/artifact line
shared a line and the Withdraw control butted against the text.

Split label and detail into their own lines, right-align the row action,
mute withdrawn tombstones, and keep long receipt ids wrapping inside the
card. Verified on a 390px viewport: queued, withdrawn, and offer rows are
separately legible with no horizontal overflow.

styles.css

@@ -59,3 +59,14 @@ main{display:block}.eyebrow{font-size:11px;font-weight:800;letter-spacing:.1em;t
 .chat-citation{min-height:32px;padding:5px 10px;border:1px solid #bcdfd4;border-radius:999px;background:var(--surface);color:var(--teal);font-weight:800;font-size:11px;cursor:pointer}
 .chat-citation:active{background:#e9f5f0}
 .chat-unverified{margin:9px 0 0;padding-top:8px;border-top:1px solid rgba(55,40,31,.09);font-size:11px;line-height:1.4;font-weight:700;color:#8a5a12}
+
+/* Issue #24 — an opt-in receipt and its tombstone must read as separate facts, not one run-on line. */
+.contribution-list{display:flex;flex-direction:column;margin-top:10px}
+.training-consent h3{font-size:13px;margin:16px 0 2px}
+.contribution-row{display:flex;align-items:center;justify-content:space-between;gap:12px;padding:11px 0;border-top:1px solid var(--line)}
+.contribution-row:first-child{border-top:0}
+.contribution-row>div{display:flex;flex-direction:column;gap:3px;min-width:0}
+.contribution-row strong{font-size:13px;line-height:1.3}
+.contribution-row span{font-size:11px;line-height:1.4;color:var(--muted);overflow-wrap:anywhere}
+.contribution-row .btn{min-height:40px;padding:0 14px;font-size:12px;flex:0 0 auto}
+.contribution-row.withdrawn strong{color:var(--muted)}