feat(ai): inline source citations in the AI chat

Retrieval tools now register a PHI-free sourceId per record/list and stream a
data-source part with the real clinician-facing title; the system prompt asks
the model to cite facts inline as [[src:id]]. The chat renders those markers as
numbered inline citation chips (PreviewCard hover) via a Streamdown link
override, with a Sources footer fallback when the model omits markers.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

frontend/lib/ai-chat.ts

@@ -43,6 +43,16 @@ export type StepData = {
   status: "active" | "complete";
 };
 
+// A citable source the agent retrieved (one per display-tool call). The model
+// references it inline via a [[src:id]] marker; the client renders that marker
+// as an inline citation chip and a sources footer. `title` is the real,
+// clinician-facing label; `id` is PHI-free (s1, s2, …).
+export type SourceData = {
+  id: string;
+  title: string;
+  kind: string;
+};
+
 // Read-only list cards (display actions).
 export type AppointmentListData = { appointments: Appointment[] };
 export type TaskListData = { tasks: Task[] };
@@ -85,6 +95,7 @@ export type TemetroDataParts = {
   importPreview: ImportPreviewData;
   veilNotice: VeilNoticeData;
   step: StepData;
+  source: SourceData;
   appointmentList: AppointmentListData;
   taskList: TaskListData;
   prescriptionList: PrescriptionListData;

frontend/lib/i18n/locales/en/translation.json

@@ -947,6 +947,19 @@
     "thinking": "Thinking…",
     "steps": "Steps",
     "reasoning": "Reasoning",
+    "sources": {
+      "title": "Sources",
+      "kind": {
+        "patient": "Patient record",
+        "lab": "Lab results",
+        "appointments": "Schedule",
+        "tasks": "Tasks",
+        "prescriptions": "Prescriptions",
+        "clinic": "Clinic",
+        "analytics": "Analytics",
+        "inventory": "Inventory"
+      }
+    },
     "graphCard": {
       "label": "Record graph"
     },