fix(web): resolve Svelte 5 mount and effect_orphan errors

Wrap router $effect in initRouter() called from App.svelte component
context to fix effect_orphan. Add resolve.conditions=['browser'] to
vite.config.ts so Vite picks the client entry point instead of the
server one (Svelte 5.50 changed package.json exports). Also add
justfile dev recipe for running daemon + web dev server together.

Co-Authored-By: Claude Opus 4.6 <[e-mail]>

justfile

···
 web-build:
     cd web && bun run build
 
+# Run daemon and web dev server together
+dev:
+    #!/usr/bin/env bash
+    trap 'kill 0' EXIT
+    cargo run -- daemon start &
+    cd web && bun run dev &
+    wait
+
 # Run the web UI dev server
 web-dev:
     cd web && bun run dev

web/src/App.svelte

···
    * Manages WebSocket connection and dispatches events to stores.
    */
 
-  import { getCurrentRoute, routerState } from './router.svelte';
+  import { getCurrentRoute, initRouter, routerState } from './router.svelte';
   import { createWsConnection } from './api/websocket';
   import { handleWsEvent as handleGraphWsEvent } from './stores/graph.svelte';
   import { handleWsEvent as handleAgentsWsEvent } from './stores/agents.svelte';
···
   import SessionHistory from './views/SessionHistory.svelte';
   import GraphSearch from './views/GraphSearch.svelte';
   import Placeholder from './views/Placeholder.svelte';
+
+  // Initialize hash-based router (must run in component context)
+  initRouter();
 
   let wsConnection: ReturnType<typeof createWsConnection> | null = null;
 

web/src/router.svelte.ts

···
 
 /**
  * Initialize the router and listen for hash changes.
- * The $effect handles setup and cleanup automatically.
+ * Must be called from within a component's reactive context (e.g., App.svelte).
  */
-$effect(() => {
-  const handler = () => {
-    // Parse the hash and update routerState
-    let hash = window.location.hash;
-    // Remove leading '#'
-    if (hash.startsWith('#')) {
-      hash = hash.slice(1);
-    }
-    routerState.path = hash === '' ? '/' : hash;
-  };
+export function initRouter(): void {
+  $effect(() => {
+    const handler = () => {
+      // Parse the hash and update routerState
+      let hash = window.location.hash;
+      // Remove leading '#'
+      if (hash.startsWith('#')) {
+        hash = hash.slice(1);
+      }
+      routerState.path = hash === '' ? '/' : hash;
+    };
 
-  // Parse current hash on init
-  handler();
+    // Parse current hash on init
+    handler();
 
-  // Listen for hash changes
-  window.addEventListener('hashchange', handler);
+    // Listen for hash changes
+    window.addEventListener('hashchange', handler);
 
-  // Return cleanup function
-  return () => {
-    window.removeEventListener('hashchange', handler);
-  };
-});
+    // Return cleanup function
+    return () => {
+      window.removeEventListener('hashchange', handler);
+    };
+  });
+}

web/vite.config.ts

···
 
 export default defineConfig({
   plugins: [svelte()],
+  resolve: {
+    conditions: ['browser'],
+  },
   build: {
     outDir: 'dist',
   },