feat(ui): add breadcrumb icons, fix alignment, and remove duplicate form headers

- add section icons to all breadcrumbs across every page
- fix breadcrumb nav display:flex so icons align vertically with buttons
- wrap all page breadcrumbs in pageToolbar div for consistent layout
- add Breadcrumbs to AllRunsPage which previously used a plain h1
- fix envCardHeader flex:1 so settings button hugs the right edge
- remove card header from environment create/edit forms (duplicated breadcrumb)

client/src/ui/Breadcrumbs/Breadcrumbs.module.css

@@ -1,4 +1,6 @@
 .nav {
+  display: flex;
+  align-items: center;
   font-family: var(--font-family);
 }
 
@@ -19,6 +21,9 @@
 }
 
 .link {
+  display: inline-flex;
+  align-items: center;
+  gap: var(--space-1);
   font-size: var(--font-size-sm);
   color: var(--color-text-muted);
   text-decoration: none;
@@ -42,6 +47,9 @@
 }
 
 .current {
+  display: inline-flex;
+  align-items: center;
+  gap: var(--space-1);
   font-size: var(--font-size-sm);
   font-weight: 600;
   color: var(--color-text);