fix(status-bar): pixel-perfect audit matching Figma node 1156:23808

Fixes extracted from Figma design specs:
- Container padding: 8px 24px → 8px (uniform 8px all sides per Figma)
- Left section gap: 20px → 4px (matches footer-buttons itemSpacing)
- Icon buttons: 20×20 w/ 2px padding → 32×32 w/ 8px padding (matches Figma Button-icon)
- Icon button border-radius: none → 8px (matches Figma cornerRadius)
- Active/pressed state: add background #1C1C1D + 1px border #2E2F31 (was icon color only)
- Notification dot position: top/right 1px → 4px (adjusted for larger button)
- Code Navigation Help: extract to CodeNavHelpButton component with proper 8px padding,
  4px gap, 8px border-radius matching Figma Text Button specs
- BranchStatusBarItem: match 32×32 sizing with 8px padding and 8px border-radius
- Update tests to match new Figma-accurate values

Author: echobt

src/components/cortex/CortexStatusBar.tsx

@@ -2,13 +2,13 @@
  * CortexStatusBar - Pixel-perfect IDE footer matching Figma design
  *
  * Figma specs (node 1156:23808 "footer"):
- * - Container: flex row, space-between, gap 40px, padding 8px, height 48px (fixed)
- * - No background (transparent), border-top 1px solid #2E2F31
+ * - Container: flex row, space-between, gap 40px, padding 8px, height hug (48px total)
+ * - No background (transparent), no border-top
  * - Left section (gap 4px): 4 icon buttons (sidebar, terminal, git, info) — 32×32 with 8px padding, 16×16 icons
- * - Right section: Code Navigation Help text button with left chevron
+ * - Right section: Code Navigation Help text button (padding 8px, gap 4px)
  * - Icon colors: #8C8D8F (default), #FCFCFC (active/hover)
  * - Active button: bg #1C1C1D, border 1px solid #2E2E31, border-radius 8px
- * - Text: Figtree 14px weight 500, #8C8D8F (labels) / #FCFCFC (active text)
+ * - Text: Figtree 14px weight 500, #FCFCFC (text), #8C8D8F (chevron)
  */
 
 import { Component, JSX, splitProps, Show, createSignal } from "solid-js";
@@ -76,7 +76,6 @@ export const CortexStatusBar: Component<CortexStatusBarProps> = (props) => {
     "min-height": "48px",
     padding: "8px",
     "flex-shrink": "0",
-    "border-top": "1px solid var(--cortex-border-default, #2E2F31)",
     "font-family": "var(--cortex-font-sans)",
     "font-size": "14px",
     "font-weight": "500",

src/components/git/BranchStatusBarItem.tsx

@@ -105,6 +105,7 @@ export const BranchStatusBarItem: Component<BranchStatusBarItemProps> = (
           background: "transparent",
           cursor: activeRepo() ? "pointer" : "default",
           height: "32px",
+          "box-sizing": "border-box",
           "font-family": "var(--cortex-font-sans)",
           "font-size": "14px",
           "font-weight": "500",