fix: reduce font size and compact all views to fit screen

Base font: clamp(10px, 0.75vw, 16px) — much smaller scaling.
At 1920px viewport = ~14px, at 3840px = 16px (capped).

All components heavily compacted:
- Header: minimal padding, smaller text
- Topology: tight InfraCards, small VmPills, 3-col VM grid
- Kanban: 3-col project grid, compact cards
- Calendar: tighter spacing
- Summary bars: single-line, text-xs

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

frontend/src/index.css

@@ -21,7 +21,8 @@
 }
 
 html {
-  font-size: clamp(14px, 1.15vw, 24px);
+  /* Scales with viewport: ~14px at 1920w, ~16px at 3840w, min 10px */
+  font-size: clamp(10px, 0.75vw, 16px);
 }
 
 body {
@@ -35,12 +36,12 @@ body {
 }
 
 ::-webkit-scrollbar {
-  width: 6px;
+  width: 4px;
 }
 ::-webkit-scrollbar-track {
   background: transparent;
 }
 ::-webkit-scrollbar-thumb {
   background: var(--color-border);
-  border-radius: 3px;
+  border-radius: 2px;
 }