Merge feat/vocabulary-hint: names-and-terms decoder prompt (spec 001 workstream 2)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

# Conflicts:
#	docs/Architecture.md
#	docs/Decisions.md
#	docs/WorkBreakdown.md
#	server-py/sidecar.py
#	src/App.tsx
#	src/server/live.ts
#	src/server/transcribe.ts
#	tests/fixtures/fake_sidecar.py
#	tests/transcribe.test.ts

src/index.css

@@ -519,6 +519,60 @@ body {
   flex-wrap: wrap;
 }
 
+/* --- VocabularyHint (D-WS2a) --- */
+
+.vocabulary-hint {
+  display: flex;
+  flex-direction: column;
+  gap: 0.35rem;
+}
+
+.vocabulary-hint-label {
+  font-size: 0.85rem;
+  color: var(--muted);
+}
+
+.vocabulary-hint-optional {
+  font-weight: 400;
+  opacity: 0.85;
+}
+
+.vocabulary-hint-input {
+  width: 100%;
+  box-sizing: border-box;
+  min-height: 2.9rem;
+  resize: vertical;
+  background: var(--surface-raised);
+  color: var(--fg);
+  border: 1px solid var(--border);
+  border-radius: 8px;
+  padding: 0.45rem 0.6rem;
+  font: inherit;
+  font-size: 0.9rem;
+  line-height: 1.4;
+  transition: border-color 0.15s;
+}
+
+.vocabulary-hint-input::placeholder {
+  color: var(--muted);
+}
+
+.vocabulary-hint-input:focus-visible {
+  border-color: var(--accent);
+  outline: none;
+}
+
+.vocabulary-hint-input:disabled {
+  opacity: 0.6;
+  cursor: not-allowed;
+}
+
+.vocabulary-hint-help {
+  margin: 0;
+  font-size: 0.8rem;
+  color: var(--muted);
+}
+
 /* --- EngineToggle (M5, D-010) --- */
 
 .engine-toggle {