Task 4b: Fix PatientBanner scroll condensation

Root cause: sentinel element with `absolute top-0` inside PatientBanner was
positioned at viewport top, always triggering the IntersectionObserver's
-100px rootMargin threshold — banner was permanently stuck in condensed state.

Fix: Restructured PMRInterface layout from document-scroll to flex container
with explicit scroll container (`overflow-y-auto` on main). Lifted scroll
condensation logic to PMRInterface, passing `isCondensed` prop down to
PatientBanner. Replaced IntersectionObserver with scroll event listener on
the main element for reliable scroll position detection.

Key changes:
- PMRInterface: flex h-screen overflow-hidden layout (sidebar + content column)
- PatientBanner: accepts isCondensed prop, removed sticky/sentinel/hook
- ClinicalSidebar: h-full instead of h-screen sticky (parent handles sizing)
- useScrollCondensation: scroll event on container element via callback ref

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

src/components/ClinicalSidebar.tsx

@@ -168,7 +168,7 @@ export function ClinicalSidebar({ activeView, onViewChange, isTablet = false }:
       <aside
         role="navigation"
         aria-label="Clinical record navigation"
-        className="hidden md:flex lg:hidden flex-col w-14 h-screen sticky top-0 bg-pmr-sidebar text-white"
+        className="hidden md:flex lg:hidden flex-col w-14 h-full bg-pmr-sidebar text-white"
       >
         <div className="p-2 border-b border-white/10">
           <div className="font-inter font-medium text-[10px] text-white/50 text-center leading-tight">
@@ -230,7 +230,7 @@ export function ClinicalSidebar({ activeView, onViewChange, isTablet = false }:
     <aside
       role="navigation"
       aria-label="Clinical record navigation"
-      className="hidden lg:flex flex-col w-[220px] h-screen sticky top-0 bg-pmr-sidebar text-white"
+      className="hidden lg:flex flex-col w-[220px] h-full bg-pmr-sidebar text-white"
     >
       <div className="p-4 border-b border-white/10">
         <div className="font-inter font-medium text-[13px] text-white/50 leading-tight">