fix(types): KI-270 — Frontend UserProfile schema add 3 missing slots

Closes the typing gap D1 flagged after KI-269: backend added
desired_sum_insured_inr (B5), copay_pct (D2), family_medical_history (D2)
to the Profile dataclass, but the frontend TS type was lagging.

frontend/src/lib/api.ts:
- UserProfile.desired_sum_insured_inr?: number (B5/KI-258)
- UserProfile.copay_pct?: number (D2/KI-269)
- UserProfile.family_medical_history?: string[](D2/KI-269)

frontend/src/app/page.tsx::PremiumCalculatorPanel:
- SI prefill now prefers desired_sum_insured_inr (the canonical target)
over existing_cover_inr (D1's typed-proxy fallback), with 1_000_000
ultimate fallback. Closes the typed-proxy workaround.

Verification:
- npx tsc --noEmit: clean
- npx next build: Compiled successfully, 4/4 static pages generated
- desired_sum_insured_inr now referenced in both api.ts type + page.tsx prefill

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

frontend/src/app/page.tsx

@@ -2145,10 +2145,14 @@ function PremiumCalculatorPanel({
   };
 
   const [age, setAge] = useState<number>(initialProfile?.age ?? 35);
+  // KI-258 (B5, 2026-05-15) — Prefer `desired_sum_insured_inr` (the user's
+  // stated target SI from chat/extractor) over `existing_cover_inr` (what
+  // they already hold). Fall back to legacy 10L default when both are
+  // missing.
   const [sumInsured, setSumInsured] = useState<number>(
-    initialProfile?.existing_cover_inr && initialProfile.existing_cover_inr > 0
-      ? initialProfile.existing_cover_inr
-      : 1000000,
+    initialProfile?.desired_sum_insured_inr ??
+      initialProfile?.existing_cover_inr ??
+      1_000_000,
   );
   const [cityTier, setCityTier] = useState<"metro" | "tier1" | "tier2">(
     deriveCityTier(initialProfile?.location_tier),

frontend/src/lib/api.ts

@@ -424,6 +424,14 @@ export type UserProfile = {
   parents_has_ped?: boolean | null;
   health_conditions?: string[] | null;
   budget_band?: string | null;
+  // KI-258 (B5, 2026-05-15) — Desired sum insured slot. Backend's pricing
+  // endpoint + retrieve_policies query both read this; frontend pre-fills
+  // the PremiumCalculatorPanel SI slider from it when present.
+  desired_sum_insured_inr?: number;
+  // KI-269 (D2, 2026-05-15) — Co-pay % the user is willing to accept.
+  copay_pct?: number;
+  // KI-269 (D2, 2026-05-15) — Family medical history (free-text tags).
+  family_medical_history?: string[];
 };
 
 export type ProfileCompletenessResponse = {