refactor: organize frontend components into features/ directories

Moved 43 component files into 9 feature domains:
- features/git/ — commit-dialog, commit-panel, file-editor, git-mount-editor,
  git-toolbar, merge-dialog
- features/project/ — repositories-settings-tab, repository-create-dialog
- features/terminal/ — special-keys-panel, special-keys-strip,
  terminal-session-tabs, terminal
- features/workspace/ — workspace-card, workspace-create-form,
  workspace-header, workspace-instance-chips
- features/session/ — create-session-form, session-card, session-list
- features/tool/ — instance-list, manifest-editor, start-tool-fab,
  start-tool-modal, tool-starter, tools-bottom-sheet
- features/notification/ — event-toast-bridge, notification-center,
  notification-item
- features/settings/ — settings-tab-layout
- features/mobile/ — mobile-action-sheet, mobile-detail-view, mobile-edit-view,
  mobile-fab, mobile-list-view, mobile-nav, mobile-page-header,
  mobile-terminal-header, mobile-terminal-wrapper

Updated all imports across pages and components.
Root components/ now only contains generic UI pieces:
app-shell, code-editor, data-states, icon, protected-route, syntax-highlighter.

Quality gates: verified no remaining old imports.

apps/web/src/components/features/workspace/workspace-card.tsx

@@ -0,0 +1,77 @@
+/** Card component for displaying a workspace. */
+
+import { Link } from "react-router-dom";
+import { Icon } from "./icon";
+import { WorkspaceInstanceChips } from "./workspace-instance-chips";
+import type { Workspace } from "../types/workspace";
+
+export interface WorkspaceCardProps {
+	workspace: Workspace;
+	loading?: boolean;
+	onStartTool: (workspace: Workspace) => void;
+	onSync: (workspace: Workspace) => void;
+	onDelete: (workspace: Workspace) => void;
+}
+
+export function WorkspaceCard({
+	workspace,
+	loading = false,
+	onStartTool,
+	onSync,
+	onDelete,
+}: WorkspaceCardProps) {
+	const statusClass =
+		workspace.status === "ready"
+			? "status-ready"
+			: workspace.status === "syncing"
+				? "status-syncing"
+				: "status-error";
+
+	return (
+		<article className={`card workspace-card ${loading ? "loading" : ""}`}>
+			<Link
+				to={`/workspaces/${workspace.id}`}
+				className="workspace-header-link"
+			>
+				<div className="workspace-header">
+					<h4>{workspace.name}</h4>
+					<span className={`status-badge ${statusClass}`}>
+						{workspace.status}
+					</span>
+				</div>
+			</Link>
+			<div className="workspace-meta">
+				<p className="workspace-project">
+					{workspace.project_name} / {workspace.repo_name}
+				</p>
+				<p className="workspace-branch">
+					<Icon name="branch" size="sm" /> {workspace.branch}
+				</p>
+				<WorkspaceInstanceChips workspaceId={workspace.id} />
+			</div>
+			<div className="workspace-actions">
+				<button
+					className="btn btn-primary"
+					onClick={() => onStartTool(workspace)}
+					disabled={loading}
+				>
+					<Icon name="play" size="sm" /> Start Tool
+				</button>
+				<button
+					className="btn btn-secondary"
+					onClick={() => onSync(workspace)}
+					disabled={loading}
+				>
+					<Icon name="refresh" size="sm" /> Sync
+				</button>
+				<button
+					className="btn btn-danger"
+					onClick={() => onDelete(workspace)}
+					disabled={loading}
+				>
+					<Icon name="delete" size="sm" /> Delete
+				</button>
+			</div>
+		</article>
+	);
+}