🤖 refactor: make workspace count visually subordinate to project name (#3128)

## Summary

Make the workspace count indicator in the project sidebar visually
subordinate to the project name, establishing a clear text hierarchy.

## Background

The workspace count next to each project name in the left sidebar was
styled identically to the project name (same size, same color). This
made them compete for visual attention instead of the count being a
quiet secondary detail.

## Implementation

Changes to the count `<span>` in `ProjectSidebar.tsx`:

- **Size:** `text-sm` → `text-xs` (smaller than the project name)
- **Color:** Stepped down one level in both states —
`text-content-primary` → `text-content-secondary` (attention),
`text-content-secondary` → `text-muted` (normal)
- **Alignment:** `items-center` → `items-baseline` on the flex container
so the smaller count text sits on the same text baseline as the project
name instead of being vertically offset

---

_Generated with `mux` • Model: `anthropic:claude-opus-4-6` • Thinking:
`xhigh` • Cost: `$0.85`_

<!-- mux-attribution: model=anthropic:claude-opus-4-6 thinking=xhigh
costs=0.85 -->

Author: ammar-agent

src/browser/components/ProjectSidebar/ProjectSidebar.tsx

@@ -1910,7 +1910,7 @@ const ProjectSidebarInner: React.FC<ProjectSidebarProps> = ({
                                     }}
                                   />
                                 ) : (
-                                  <div className="text-muted-dark flex min-w-0 items-center gap-1.5 text-sm">
+                                  <div className="text-muted-dark flex min-w-0 items-baseline gap-1.5 text-sm">
                                     <span
                                       className={cn(
                                         "min-w-0 flex-1 truncate font-medium",
@@ -1923,10 +1923,10 @@ const ProjectSidebarInner: React.FC<ProjectSidebarProps> = ({
                                     </span>
                                     <span
                                       className={cn(
-                                        "shrink-0",
+                                        "shrink-0 text-xs",
                                         projectHasAttention
-                                          ? "text-content-primary"
-                                          : "text-content-secondary"
+                                          ? "text-content-secondary"
+                                          : "text-muted"
                                       )}
                                     >
                                       ({projectAgentCount})