feat(v3): project-level tabs + clean AgentPane + ProjectHeader info bar

- ProjectBox: Claude|Files|Context tab bar switching content area
- ProjectFiles.svelte: project-scoped markdown file viewer
- ProjectHeader: CWD (ellipsized from start) + profile as info text
- AgentPane: removed DIR/ACC toolbar, CWD+profile now props from parent
- ClaudeSession: passes project.profile to AgentPane

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

@@ -5,6 +5,8 @@
   import ClaudeSession from './ClaudeSession.svelte';
   import TerminalTabs from './TerminalTabs.svelte';
   import TeamAgentsPanel from './TeamAgentsPanel.svelte';
+  import ProjectFiles from './ProjectFiles.svelte';
+  import ContextPane from '../Context/ContextPane.svelte';
 
   interface Props {
     project: ProjectConfig;
@@ -17,6 +19,9 @@
 
   let accentVar = $derived(PROJECT_ACCENTS[slotIndex % PROJECT_ACCENTS.length]);
   let mainSessionId = $state<string | null>(null);
+
+  type ProjectTab = 'claude' | 'files' | 'context';
+  let activeTab = $state<ProjectTab>('claude');
 </script>
 
 <div
@@ -31,10 +36,40 @@
     onclick={onactivate}
   />
 
-  <div class="project-session-area">
-    <ClaudeSession {project} onsessionid={(id) => mainSessionId = id} />
-    {#if mainSessionId}
-      <TeamAgentsPanel {mainSessionId} />
+  <div class="project-tabs">
+    <button
+      class="ptab"
+      class:active={activeTab === 'claude'}
+      onclick={() => activeTab = 'claude'}
+    >Claude</button>
+    <button
+      class="ptab"
+      class:active={activeTab === 'files'}
+      onclick={() => activeTab = 'files'}
+    >Files</button>
+    <button
+      class="ptab"
+      class:active={activeTab === 'context'}
+      onclick={() => activeTab = 'context'}
+    >Context</button>
+  </div>
+
+  <div class="project-content-area">
+    {#if activeTab === 'claude'}
+      <div class="content-pane">
+        <ClaudeSession {project} onsessionid={(id) => mainSessionId = id} />
+        {#if mainSessionId}
+          <TeamAgentsPanel {mainSessionId} />
+        {/if}
+      </div>
+    {:else if activeTab === 'files'}
+      <div class="content-pane">
+        <ProjectFiles cwd={project.cwd} projectName={project.name} />
+      </div>
+    {:else if activeTab === 'context'}
+      <div class="content-pane">
+        <ContextPane onExit={() => {}} />
+      </div>
     {/if}
   </div>
 
@@ -46,7 +81,7 @@
 <style>
   .project-box {
     display: grid;
-    grid-template-rows: auto 1fr auto;
+    grid-template-rows: auto auto 1fr auto;
     min-width: 30rem;
     scroll-snap-align: start;
     background: var(--ctp-base);
@@ -60,13 +95,50 @@
     border-color: var(--accent);
   }
 
-  .project-session-area {
+  .project-tabs {
     display: flex;
+    gap: 0;
+    background: var(--ctp-mantle);
+    border-bottom: 1px solid var(--ctp-surface0);
+    flex-shrink: 0;
+  }
+
+  .ptab {
+    padding: 0.25rem 0.75rem;
+    background: transparent;
+    border: none;
+    border-bottom: 2px solid transparent;
+    color: var(--ctp-overlay1);
+    font-size: 0.7rem;
+    font-weight: 500;
+    cursor: pointer;
+    text-transform: uppercase;
+    letter-spacing: 0.04em;
+    transition: color 0.1s, border-color 0.1s;
+  }
+
+  .ptab:hover {
+    color: var(--ctp-text);
+  }
+
+  .ptab.active {
+    color: var(--ctp-text);
+    border-bottom-color: var(--accent);
+    font-weight: 600;
+  }
+
+  .project-content-area {
     overflow: hidden;
     position: relative;
     min-height: 0;
   }
 
+  .content-pane {
+    display: flex;
+    height: 100%;
+    overflow: hidden;
+  }
+
   .project-terminal-area {
     height: 16rem;
     min-height: 8rem;