feat: Users AI Chat multi-step workflows with CDT lookup and alias management

- Add eligibility_by_id and check_and_claim intents to internal chat
- New cdt-lookup.ts: keyword search against fee schedule JSON (no LLM)
- New internal-chat-workflow.ts: deterministic orchestration — patient
  resolution, insurance siteKey derivation, CDT code mapping
- Custom CDT aliases stored per-user in DB (TwilioSettings JSON blob)
  with GET/PUT /api/ai/cdt-aliases endpoints
- Chatbot UI: new steps for eligibility-id-ready, check-and-claim-ready,
  and need-insurance-clarification with insurance picker
- Settings UI: CDT Aliases CRUD table with built-in alias reference

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

apps/Backend/src/storage/twilio-storage.ts

@@ -137,6 +137,27 @@ export const twilioStorage = {
     });
   },
 
+  async getCdtAliases(userId: number): Promise<{ phrase: string; cdtCode: string }[]> {
+    const settings = await db.twilioSettings.findUnique({ where: { userId } });
+    const all = (settings?.templates as Record<string, any>) || {};
+    const raw = all["_cdt_aliases"];
+    if (!Array.isArray(raw)) return [];
+    return raw.filter(
+      (r: any) => typeof r?.phrase === "string" && typeof r?.cdtCode === "string"
+    );
+  },
+
+  async saveCdtAliases(userId: number, aliases: { phrase: string; cdtCode: string }[]): Promise<void> {
+    const settings = await db.twilioSettings.findUnique({ where: { userId } });
+    const existing = (settings?.templates as Record<string, any>) || {};
+    const updated = { ...existing, "_cdt_aliases": aliases };
+    await db.twilioSettings.upsert({
+      where:  { userId },
+      update: { templates: updated },
+      create: { userId, accountSid: "", authToken: "", phoneNumber: "", templates: updated },
+    });
+  },
+
   async getRecentCommunicationsByUser(userId: number, limit = 20) {
     return db.communication.findMany({
       where: { patient: { userId } },