fix: card-level buttons use ghost/outline instead of solid primary

Repeated per-card action buttons (Start Session, Resume, Save, Insert,
Start batch) now use cyan outline style to reduce visual noise.
Page-level and modal primary actions remain solid cyan.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/src/components/dashboard/OpenSessions.tsx

@@ -52,7 +52,7 @@ export function OpenSessions({ sessions }: OpenSessionsProps) {
               <Link
                 to={getTreeNavigatePath(session.treeId, session.treeType)}
                 state={{ sessionId: session.id }}
-                className="shrink-0 rounded-lg bg-primary px-3 py-1 text-[0.6875rem] font-medium text-white hover:brightness-110 transition-opacity"
+                className="shrink-0 rounded-lg border border-primary/40 px-3 py-1 text-[0.6875rem] font-medium text-primary hover:bg-primary/10 hover:border-primary/60 transition-colors"
               >
                 Resume
               </Link>

frontend/src/components/library/TreeGridView.tsx

@@ -163,8 +163,8 @@ export function TreeGridView({
                 type="button"
                 onClick={() => onStartSession(tree.id, tree.tree_type)}
                 className={cn(
-                  'rounded-md bg-primary px-3 py-2 text-sm font-medium text-white',
+                  'rounded-md border border-primary/40 px-3 py-2 text-sm font-medium text-primary',
-                  'hover:brightness-110'
+                  'hover:bg-primary/10 hover:border-primary/60 transition-colors'
                 )}
               >
                 Start Session

frontend/src/components/library/TreeListView.tsx

@@ -166,8 +166,8 @@ export function TreeListView({
                 type="button"
                 onClick={() => onStartSession(tree.id, tree.tree_type)}
                 className={cn(
-                  'rounded-md bg-primary px-3 py-1.5 text-sm font-medium text-white',
+                  'rounded-md border border-primary/40 px-3 py-1.5 text-sm font-medium text-primary',
-                  'hover:brightness-110 whitespace-nowrap'
+                  'hover:bg-primary/10 hover:border-primary/60 transition-colors whitespace-nowrap'
                 )}
               >
                 Start

frontend/src/components/library/TreeTableView.tsx

@@ -270,8 +270,8 @@ export function TreeTableView({
                     type="button"
                     onClick={() => onStartSession(tree.id, tree.tree_type)}
                     className={cn(
-                      'rounded-md bg-primary px-3 py-1.5 text-xs font-medium text-white',
+                      'rounded-md border border-primary/40 px-3 py-1.5 text-xs font-medium text-primary',
-                      'hover:brightness-110 whitespace-nowrap'
+                      'hover:bg-primary/10 hover:border-primary/60 transition-colors whitespace-nowrap'
                     )}
                   >
                     Start

frontend/src/components/maintenance/BatchStatusCard.tsx

@@ -132,7 +132,7 @@ export function BatchStatusCard({ session, targetLabel, treeId, batchId }: Batch
         {isNotStarted && (
           <button
             onClick={handleStart}
-            className="flex items-center gap-1.5 rounded-lg bg-primary px-3 py-1.5 text-[0.8125rem] font-medium text-white hover:brightness-110 transition-opacity"
+            className="flex items-center gap-1.5 rounded-lg border border-primary/40 px-3 py-1.5 text-[0.8125rem] font-medium text-primary hover:bg-primary/10 hover:border-primary/60 transition-colors"
           >
             <Play className="h-3.5 w-3.5" />
             Start

frontend/src/components/step-library/StepCard.tsx

@@ -188,7 +188,7 @@ export function StepCard({ step, onPreview, onInsert, onEdit, onDelete, onSave,
               </button>
               <button
                 onClick={() => onSave?.(step)}
-                className="flex flex-1 items-center justify-center gap-2 rounded-md bg-primary text-white px-3 py-2 text-sm font-medium hover:brightness-110 transition-colors"
+                className="flex flex-1 items-center justify-center gap-2 rounded-md border border-primary/40 text-primary px-3 py-2 text-sm font-medium hover:bg-primary/10 hover:border-primary/60 transition-colors"
               >
                 <Bookmark className="h-4 w-4" />
                 Save
@@ -207,7 +207,7 @@ export function StepCard({ step, onPreview, onInsert, onEdit, onDelete, onSave,
             </button>
             <button
               onClick={() => onInsert?.(step)}
-              className="flex flex-1 items-center justify-center gap-2 rounded-md bg-primary text-white px-3 py-2 text-sm font-medium hover:brightness-110 transition-colors"
+              className="flex flex-1 items-center justify-center gap-2 rounded-md border border-primary/40 text-primary px-3 py-2 text-sm font-medium hover:bg-primary/10 hover:border-primary/60 transition-colors"
             >
               <Plus className="h-4 w-4" />
               Insert