feat(v2): scaffold Tauri 2.x + Svelte 5 project (Phase 1)

- Tauri 2.10 + Svelte 5.45 + TypeScript + Vite 7
- Catppuccin Mocha theme with CSS variables and semantic aliases
- CSS Grid layout: sidebar (260px) + workspace, responsive breakpoints
  for ultrawide (3440px+) and narrow (<1200px)
- Component structure: Layout/, Terminal/, Agent/, Markdown/, Sidebar/
- Svelte 5 stores with $state runes: sessions, agents, layout
- SDK message adapter (abstracts Agent SDK wire format)
- PTY bridge (Tauri IPC wrapper, stubbed for Phase 2)
- Node.js sidecar entry point (stdio NDJSON, stubbed for Phase 3)
- Rust modules: pty, sidecar, watcher, session (stubbed)
- Vite dev server on port 9700
- Build verified: binary + .deb + .rpm + AppImage all produced

v2/src/lib/stores/agents.ts

@@ -0,0 +1,34 @@
+// Agent tracking state — Svelte 5 runes
+// Phase 3: SDK agent lifecycle, subagent tree
+
+export type AgentStatus = 'idle' | 'running' | 'thinking' | 'waiting' | 'done' | 'error';
+
+export interface AgentState {
+  id: string;
+  sessionId: string;
+  parentId?: string;
+  status: AgentStatus;
+  model?: string;
+  costUsd?: number;
+  tokensIn?: number;
+  tokensOut?: number;
+}
+
+let agents = $state<AgentState[]>([]);
+
+export function getAgents() {
+  return agents;
+}
+
+export function getAgentTree(rootId: string): AgentState[] {
+  const result: AgentState[] = [];
+  const root = agents.find(a => a.id === rootId);
+  if (!root) return result;
+
+  result.push(root);
+  const children = agents.filter(a => a.parentId === rootId);
+  for (const child of children) {
+    result.push(...getAgentTree(child.id));
+  }
+  return result;
+}