feat(v3): implement Mission Control MVP (Phases 1-5)

Phase 1: Data model - groups.rs (Rust structs + load/save groups.json),
groups.ts (TypeScript interfaces), groups-bridge.ts (IPC adapter),
workspace.svelte.ts (replaces layout store), SQLite migrations
(agent_messages, project_agent_state tables, project_id column),
--group CLI argument.

Phase 2: Project shell layout - GlobalTabBar, ProjectGrid, ProjectBox,
ProjectHeader, CommandPalette, DocsTab, ContextTab, SettingsTab,
App.svelte full rewrite (no sidebar/TilingGrid).

Phase 3: ClaudeSession.svelte wrapping AgentPane per-project.
Phase 4: TerminalTabs.svelte with shell/SSH/agent tab types.
Phase 5: TeamAgentsPanel + AgentCard for compact subagent view.

Also fixes AgentPane Svelte 5 event modifier (on:click -> onclick).

v2/src/lib/components/Workspace/ProjectBox.svelte

@@ -0,0 +1,77 @@
+<script lang="ts">
+  import type { ProjectConfig } from '../../types/groups';
+  import { PROJECT_ACCENTS } from '../../types/groups';
+  import ProjectHeader from './ProjectHeader.svelte';
+  import ClaudeSession from './ClaudeSession.svelte';
+  import TerminalTabs from './TerminalTabs.svelte';
+  import TeamAgentsPanel from './TeamAgentsPanel.svelte';
+
+  interface Props {
+    project: ProjectConfig;
+    slotIndex: number;
+    active: boolean;
+    onactivate: () => void;
+  }
+
+  let { project, slotIndex, active, onactivate }: Props = $props();
+
+  let accentVar = $derived(PROJECT_ACCENTS[slotIndex % PROJECT_ACCENTS.length]);
+  let mainSessionId = $state<string | null>(null);
+</script>
+
+<div
+  class="project-box"
+  class:active
+  style="--accent: var({accentVar})"
+>
+  <ProjectHeader
+    {project}
+    {slotIndex}
+    {active}
+    onclick={onactivate}
+  />
+
+  <div class="project-session-area">
+    <ClaudeSession {project} onsessionid={(id) => mainSessionId = id} />
+    {#if mainSessionId}
+      <TeamAgentsPanel {mainSessionId} />
+    {/if}
+  </div>
+
+  <div class="project-terminal-area">
+    <TerminalTabs {project} />
+  </div>
+</div>
+
+<style>
+  .project-box {
+    display: flex;
+    flex-direction: column;
+    min-width: 480px;
+    scroll-snap-align: start;
+    background: var(--ctp-base);
+    border: 1px solid var(--ctp-surface0);
+    border-radius: 6px;
+    overflow: hidden;
+    transition: border-color 0.15s;
+  }
+
+  .project-box.active {
+    border-color: var(--accent);
+  }
+
+  .project-session-area {
+    flex: 1;
+    min-height: 200px;
+    overflow: hidden;
+    position: relative;
+    display: flex;
+  }
+
+  .project-terminal-area {
+    flex-shrink: 0;
+    min-height: 120px;
+    border-top: 1px solid var(--ctp-surface0);
+  }
+
+</style>