redact: UX overhaul — engine simplification, credits, spinner, save-to-docs, badges

- Remove GPU/regex engine options; keep only azure_mini (1 credit) and azure_full (2 credits)
- Variable credit cost: engine-aware pre-check and charge in api/redact.php; PricingCatalog base = 1
- Fix ATTORNEY not preserved when keepOfficials=true: add to LLM prompt, generic-tag, pseudonym regexes
- Replace Azure credits hint with per-engine credit cost text (all 4 languages)
- Single-file upload only (was: up to 5); simplify status messages
- Clear previous redaction output and show pulsing spinner when a new run starts
- Add "Save to My Docs" button in redact output panel (corpus-save.js path)
- corpus-save.js: capture source_doc_ids from button dataset, pass in POST payload
- api/save-to-corpus.php: accept source_doc_ids, store first as source_url=corpus-doc:{id}
- doc-picker.js: show "✂ Redacted" badge for documents saved from the redact tool
- CSS: .redact-working spinner, doc-item__badge--redact pill styles

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

assets/css/doc-picker.css

@@ -270,3 +270,23 @@
     transition: border-color 0.15s, color 0.15s;
 }
 .audio-corpus-upload:hover { border-color: var(--dbn-accent, #00205B); color: var(--dbn-accent, #00205B); }
+
+
+/* ── Redacted document badge ─────────────────────────────────────────────── */
+
+.doc-item__badge {
+    display: inline-block;
+    margin-left: 0.45em;
+    padding: 0.1em 0.45em;
+    border-radius: 4px;
+    font-size: 0.72rem;
+    font-weight: 600;
+    vertical-align: middle;
+    line-height: 1.4;
+}
+
+.doc-item__badge--redact {
+    background: #ede8f7;
+    color: #5b35a8;
+    border: 1px solid rgba(91, 53, 168, 0.2);
+}