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/ProjectHeader.svelte

@@ -0,0 +1,74 @@
+<script lang="ts">
+  import type { ProjectConfig } from '../../types/groups';
+  import { PROJECT_ACCENTS } from '../../types/groups';
+
+  interface Props {
+    project: ProjectConfig;
+    slotIndex: number;
+    active: boolean;
+    onclick: () => void;
+  }
+
+  let { project, slotIndex, active, onclick }: Props = $props();
+
+  let accentVar = $derived(PROJECT_ACCENTS[slotIndex % PROJECT_ACCENTS.length]);
+</script>
+
+<button
+  class="project-header"
+  class:active
+  style="--accent: var({accentVar})"
+  {onclick}
+>
+  <span class="project-icon">{project.icon || '\uf120'}</span>
+  <span class="project-name">{project.name}</span>
+  <span class="project-id">({project.identifier})</span>
+</button>
+
+<style>
+  .project-header {
+    display: flex;
+    align-items: center;
+    gap: 6px;
+    padding: 4px 10px;
+    height: 28px;
+    background: var(--ctp-mantle);
+    border: none;
+    border-bottom: 2px solid transparent;
+    color: var(--ctp-subtext0);
+    font-size: 0.78rem;
+    cursor: pointer;
+    flex-shrink: 0;
+    width: 100%;
+    text-align: left;
+    transition: color 0.15s, border-color 0.15s;
+  }
+
+  .project-header:hover {
+    color: var(--ctp-text);
+  }
+
+  .project-header.active {
+    color: var(--ctp-text);
+    border-bottom-color: var(--accent);
+  }
+
+  .project-icon {
+    font-family: 'NerdFontsSymbols Nerd Font', 'Symbols Nerd Font Mono', monospace;
+    font-size: 0.9rem;
+    color: var(--accent);
+  }
+
+  .project-name {
+    font-weight: 600;
+    white-space: nowrap;
+    overflow: hidden;
+    text-overflow: ellipsis;
+  }
+
+  .project-id {
+    color: var(--ctp-overlay0);
+    font-size: 0.7rem;
+    white-space: nowrap;
+  }
+</style>