feat: redesign authenticated UI with home overview and settings hub

- Add HomePage with open sessions grid, projects overview, and session composer
- Add SettingsPage with tabs for General, SSH Keys, Tool Types, Tool Configs
- Update navigation to Home, Projects, Settings
- Redirect legacy routes (/sessions, /ssh-keys, /tool-types, /tool-configs)
- Apply Inter font and warm editorial styling
- Update tests for new dashboard and projects pages

Quality gates: typecheck pass, lint pass, 15/15 tests pass

Refs: openspec/changes/ui-redesign-home-settings

apps/web/src/pages/tool-configs.tsx

@@ -1,4 +1,5 @@
 import { useCallback, useEffect, useState } from "react";
+import { useNavigate } from "react-router-dom";
 
 import { Icon } from "../components/icon";
 import { listToolTypes, type ToolType } from "../api/tool_types";
@@ -13,6 +14,7 @@ import {
 type ConfigStatus = "loading" | "ready" | "error";
 
 export const ToolConfigsPage = () => {
+  const navigate = useNavigate();
   const [status, setStatus] = useState<ConfigStatus>("loading");
   const [toolTypes, setToolTypes] = useState<ToolType[]>([]);
   const [configs, setConfigs] = useState<ToolConfig[]>([]);
@@ -135,7 +137,13 @@ export const ToolConfigsPage = () => {
   return (
     <section className="stack">
       <div className="page-header">
-        <h1>Tool Configurations</h1>
+        <div>
+          <p className="eyebrow">Settings</p>
+          <h1>Tool Configurations</h1>
+        </div>
+        <button className="secondary-button" type="button" onClick={() => navigate("/settings")}>
+          Back to settings
+        </button>
         <p className="muted">
           Manage environment variables and configuration files for your tools
         </p>