feat(web/ui): consolidate dialogs, cards, and breakpoints (Pass 3)

- Unify modal/dialog system; .modal-* are now aliases of .dialog-*
- Migrate WorkspacesPage, start-tool-modal, merge-dialog, workspace-tools-panel to .dialog-*
- Add .card-sm/.card-md/.card-lg/.card-elevated/.card-borderless modifiers
- Apply card utilities across workspaces, projects, ssh-keys, workspace-detail, git-history
- Remove duplicated card-like background/border/padding from page CSS
- Remove 860px breakpoint; standardize on 767px/768px mobile split
- Add docs/development/ui-review-checklist.md
- Archive web-ui-spacing-typography-rework OpenSpec change

apps/web/src/components/features/workspace/workspace-tools-panel.tsx

@@ -18,7 +18,7 @@ export function WorkspaceToolsPanel({ workspace }: WorkspaceToolsPanelProps) {
 		<div className="tools-tab">
 			{loading && <p className="muted">Loading instances...</p>}
 			{instances.length === 0 ? (
-				<div className="empty-state-card">
+				<div className="card card-lg empty-state-card">
 					<Icon name="terminal" size="lg" />
 					<h3>No tools running</h3>
 					<p>Start a tool to begin coding in this workspace</p>
@@ -62,8 +62,8 @@ export function WorkspaceToolsPanel({ workspace }: WorkspaceToolsPanelProps) {
 				</>
 			)}
 			{showModal && (
-				<div className="modal-overlay" onClick={() => setShowModal(false)}>
-					<div className="modal-content" onClick={(e) => e.stopPropagation()}>
+				<div className="dialog-overlay" onClick={() => setShowModal(false)}>
+					<div className="dialog" onClick={(e) => e.stopPropagation()}>
 						<h3>Start Tool</h3>
 						<ToolStarter
 							workspace={workspace}