feat(redact): tag highlighting, inventory panel, before/after toggle, gpt-4o upgrade

- CSS: colour-coded [TAG] spans by entity type (person=pink, org=blue,
  place=green, date=amber, id=purple)
- Inventory panel: collapsible list showing tag → original text mappings
  with occurrence counts, sourced from new redaction_map API response key
- Before/after toggle: Redacted / Original view-switch buttons wired to
  lastOriginalText captured at submission time
- One-click gpt-4o upgrade button when mini or GPU engine was used
- Backend: redaction_map built from applied LLM entities (tag → originals
  + occurrence count via substr_count on final text)
- renderResults now calls setupRedactViewToggle() after DOM is written

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

assets/css/tools.css

@@ -897,6 +897,115 @@ p {
   line-height: 1.55;
 }
 
+/* ── Redact: tag highlighting ── */
+.redact-tag {
+  display: inline;
+  border-radius: 4px;
+  padding: 1px 4px;
+  font-weight: 600;
+  font-size: 0.88em;
+}
+.redact-tag--person { background: #fce7f3; color: #9d174d; }
+.redact-tag--org    { background: #dbeafe; color: #1e40af; }
+.redact-tag--place  { background: #dcfce7; color: #166534; }
+.redact-tag--date   { background: #fef3c7; color: #92400e; }
+.redact-tag--id     { background: #ede9fe; color: #5b21b6; }
+
+/* ── Redact: view toggle ── */
+.redact-view-toggle {
+  display: flex;
+  gap: 6px;
+  margin-bottom: 8px;
+}
+.view-btn {
+  padding: 4px 14px;
+  border-radius: 999px;
+  border: 1px solid var(--line);
+  background: transparent;
+  color: var(--muted);
+  font-size: 0.82em;
+  cursor: pointer;
+  transition: background 0.15s, color 0.15s;
+}
+.view-btn.is-active {
+  background: var(--ink);
+  color: #fff;
+  border-color: var(--ink);
+}
+
+/* ── Redact: inventory panel ── */
+.redact-inventory {
+  margin: 10px 0 6px;
+  border: 1px solid var(--line);
+  border-radius: 8px;
+  overflow: hidden;
+}
+.redact-inventory summary {
+  padding: 8px 12px;
+  cursor: pointer;
+  font-size: 0.85em;
+  font-weight: 600;
+  color: var(--muted);
+  background: #fafafa;
+  list-style: none;
+  display: flex;
+  align-items: center;
+  gap: 8px;
+}
+.redact-inventory summary::-webkit-details-marker { display: none; }
+.inv-badge {
+  background: var(--line);
+  color: var(--muted);
+  border-radius: 999px;
+  padding: 1px 7px;
+  font-size: 0.8em;
+  font-weight: 700;
+}
+.inv-list {
+  list-style: none;
+  padding: 8px 12px;
+  margin: 0;
+  display: flex;
+  flex-direction: column;
+  gap: 6px;
+  background: #fff;
+}
+.inv-list li {
+  display: flex;
+  align-items: baseline;
+  gap: 6px;
+  font-size: 0.84em;
+  flex-wrap: wrap;
+}
+.inv-originals { color: var(--muted); }
+.inv-originals em { font-style: normal; color: var(--ink); font-weight: 500; }
+.inv-count {
+  margin-left: auto;
+  color: var(--muted);
+  font-size: 0.82em;
+  white-space: nowrap;
+}
+
+/* ── Redact: upgrade engine button ── */
+.upgrade-engine-btn {
+  display: block;
+  margin: 10px 0 4px;
+  background: none;
+  border: 1px dashed var(--line);
+  border-radius: 8px;
+  padding: 8px 14px;
+  font-size: 0.83em;
+  color: var(--muted);
+  cursor: pointer;
+  width: 100%;
+  text-align: left;
+  transition: border-color 0.15s, color 0.15s;
+}
+.upgrade-engine-btn:hover {
+  border-color: var(--ink);
+  color: var(--ink);
+}
+
 .pill-list {
   display: flex;
   flex-wrap: wrap;