feat: agent monitor characters, cast panel, WSL fixes, and Sonnet 4.6 (#149)

## Summary

### New Features
- **Claude Sonnet 4.6 support** — added `claude-sonnet-4-6` as a selectable model in the config sidebar
- **Anime girl characters for subagents** — each subagent in the agent monitor is automatically assigned one of six characters (Amari, Keiko, Minori, Reina, Tatsumi, Yumiko) with a unique name, CDN avatar, title, and lore-flavoured description; assignment avoids duplicates when possible
- **"Meet the Team" cast panel** — a new modal accessible from the status bar introduces the full cast: Naomi (Chief hEx-ecutive Officer), Hikari (Chief Operating Officer), and the six subagent girls with their C-suite titles and character bios

### Bug Fixes
- **"Already running" error on invalid working directory** — if a spawned Claude process exits unexpectedly (e.g. because the working directory doesn't exist), `try_wait()` now detects the stale handle and clears it before allowing a restart
- **Working directory pre-validation** — on Windows, the app now runs `wsl -e test -d <dir>` before launching Claude; invalid directories surface a clear error immediately
- **WSL binary detection** — on Windows, `wsl -e bash -lc "which claude"` is used to probe for the Claude binary inside WSL; on Linux/WSLg, `bash -lc "which claude"` is used as a login-shell fallback so GUI apps find the binary even without shell PATH
- **WSL detection fix for production builds** — `detect_wsl()` now short-circuits at compile time on Windows targets, preventing inherited `WSL_DISTRO_NAME` env vars from misrouting native Windows binaries through the Linux code path

✨ This PR was crafted with love by Hikari~ 🌸

Reviewed-on: #149
Co-authored-by: Hikari <hikari@nhcarrigan.com>
Co-committed-by: Hikari <hikari@nhcarrigan.com>

src/lib/components/StatusBar.svelte

@@ -27,6 +27,7 @@
   import GitPanel from "./GitPanel.svelte";
   import ProfilePanel from "./ProfilePanel.svelte";
   import AgentMonitorPanel from "./AgentMonitorPanel.svelte";
+  import CastPanel from "./CastPanel.svelte";
   import PluginManagementPanel from "./PluginManagementPanel.svelte";
   import McpManagementPanel from "./McpManagementPanel.svelte";
   import { conversationsStore } from "$lib/stores/conversations";
@@ -56,6 +57,7 @@
   let showGitPanel = $state(false);
   let showProfile = $state(false);
   let showAgentMonitor = $state(false);
+  let showCastPanel = $state(false);
   let showPluginPanel = $state(false);
   let showMcpPanel = $state(false);
   let isSummarising = $state(false);
@@ -519,6 +521,20 @@
         />
       </svg>
     </button>
+    <button
+      onclick={() => (showCastPanel = true)}
+      class="p-1 text-gray-500 icon-trans-hover"
+      title="Meet the Team"
+    >
+      <svg class="w-5 h-5" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+        <path
+          stroke-linecap="round"
+          stroke-linejoin="round"
+          stroke-width="2"
+          d="M17 20h5v-2a3 3 0 00-5.356-1.857M17 20H7m10 0v-2c0-.656-.126-1.283-.356-1.857M7 20H2v-2a3 3 0 015.356-1.857M7 20v-2c0-.656.126-1.283.356-1.857m0 0a5.002 5.002 0 019.288 0M15 7a3 3 0 11-6 0 3 3 0 016 0zm6 3a2 2 0 11-4 0 2 2 0 014 0zM7 10a2 2 0 11-4 0 2 2 0 014 0z"
+        />
+      </svg>
+    </button>
     <button
       onclick={() => (showAgentMonitor = !showAgentMonitor)}
       class="p-1 text-gray-500 icon-trans-hover relative {showAgentMonitor
@@ -737,6 +753,10 @@
   <AgentMonitorPanel isOpen={showAgentMonitor} onClose={() => (showAgentMonitor = false)} />
 {/if}
 
+{#if showCastPanel}
+  <CastPanel onClose={() => (showCastPanel = false)} />
+{/if}
+
 {#if showPluginPanel}
   <PluginManagementPanel onClose={() => (showPluginPanel = false)} />
 {/if}