feat: member portal Sprint 1 — dashboard with MemberShell layout and TowerUser profile fields

- Add avatar, hometown, currentLocation, interests, language, digestPreference, directoryVisible fields to TowerUser
- Migration: 20260617200000_add_tower_user_profile_fields
- GET /my/dashboard API endpoint with stats (groups, messages, consents)
- BFF route /api/my/dashboard
- MemberShell 3-column layout (220px nav + flex-1 main + 280px rail)
- Dashboard page: hero card, stat cards, group list, interests chips
- Sidebar returns null for /my paths (MemberShell owns the nav)

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

apps/api/prisma/migrations/20260617200000_add_tower_user_profile_fields/migration.sql

@@ -0,0 +1,7 @@
+ALTER TABLE "TowerUser" ADD COLUMN "avatar" TEXT;
+ALTER TABLE "TowerUser" ADD COLUMN "hometown" TEXT;
+ALTER TABLE "TowerUser" ADD COLUMN "currentLocation" TEXT;
+ALTER TABLE "TowerUser" ADD COLUMN "interests" TEXT[] NOT NULL DEFAULT '{}';
+ALTER TABLE "TowerUser" ADD COLUMN "language" TEXT NOT NULL DEFAULT 'en';
+ALTER TABLE "TowerUser" ADD COLUMN "digestPreference" TEXT NOT NULL DEFAULT 'daily';
+ALTER TABLE "TowerUser" ADD COLUMN "directoryVisible" BOOLEAN NOT NULL DEFAULT true;

apps/api/prisma/schema.prisma

@@ -365,14 +365,21 @@ enum MemberOptOutReason {
 
 // Hashed identity: SHA-256 of E.164 phone number (pepper via JWT_SECRET).
 model TowerUser {
-  id          String   @id @default(cuid())
-  tenantId    String
-  tenant      Tenant   @relation(fields: [tenantId], references: [id])
-  phoneHash   String
-  jid         String
-  displayName String?
-  createdAt   DateTime @default(now())
-  updatedAt   DateTime @updatedAt
+  id               String   @id @default(cuid())
+  tenantId         String
+  tenant           Tenant   @relation(fields: [tenantId], references: [id])
+  phoneHash        String
+  jid              String
+  displayName      String?
+  avatar           String?
+  hometown         String?
+  currentLocation  String?
+  interests        String[]
+  language         String   @default("en")
+  digestPreference String   @default("daily")
+  directoryVisible Boolean  @default(true)
+  createdAt        DateTime @default(now())
+  updatedAt        DateTime @updatedAt
 
   consents ConsentRecord[]
   optOuts  MemberOptOut[]