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-git-panel.tsx

@@ -28,7 +28,7 @@ export function WorkspaceGitPanel({ workspaceId }: WorkspaceGitPanelProps) {
 			{error && <p className="error-text">{error}</p>}
 			<div className="commit-history">
 				{history.map((commit) => (
-					<div key={commit.hash} className="commit-row">
+					<div key={commit.hash} className="card card-sm commit-row">
 						<span className="commit-hash">{commit.hash.slice(0, 7)}</span>
 						<span className="commit-message">{commit.message}</span>
 						<span className="commit-author">{commit.author}</span>