feat: session management fixes and sessions hub

- Add confirmation dialogs for stop/delete on dashboard
- Filter deleted sessions immediately without reload
- Add tunnel health polling with error badges
- Add Sessions nav item with active count badge
- Route /sessions to SessionsPage component

Quality gates: 43/43 tests pass, typecheck pass, lint pass

Refs: openspec/changes/session-management-fixes
Refs: openspec/changes/sessions-hub

apps/web/src/components/app-shell.tsx

@@ -9,8 +9,9 @@ import { useSessions } from "../state/sessions";
 import { Icon } from "./icon";
 import type { IconName } from "../utils/icons";
 
-const NAV_ITEMS: { to: string; label: string; icon: IconName }[] = [
+const NAV_ITEMS: { to: string; label: string; icon: IconName; badge?: "sessions" }[] = [
   { to: "/", label: "Home", icon: "dashboard" },
+  { to: "/sessions", label: "Sessions", icon: "terminal", badge: "sessions" },
   { to: "/projects", label: "Projects", icon: "projects" },
   { to: "/tool-workshop", label: "Tool Workshop", icon: "settings" },
   { to: "/settings", label: "Settings", icon: "settings" }
@@ -83,7 +84,6 @@ export const AppShell = () => {
       <div className="shell-body">
         <aside className="shell-nav" aria-label="Primary navigation">
           {NAV_ITEMS.map((item) => {
-            const isHome = item.to === "/";
             const activeCount = sessions.filter((s) => s.status === "running").length;
             return (
               <NavLink
@@ -94,7 +94,7 @@ export const AppShell = () => {
               >
                 <Icon name={item.icon} size="sm" />
                 {item.label}
-                {isHome && activeCount > 0 && (
+                {item.badge === "sessions" && activeCount > 0 && (
                   <span className="nav-badge">{activeCount}</span>
                 )}
               </NavLink>

apps/web/src/pages/dashboard.tsx

@@ -2,7 +2,7 @@ import { useCallback, useEffect, useMemo, useState } from "react";
 import { useNavigate } from "react-router-dom";
 
 import { getDashboardSummary, type DashboardSummary } from "../api/dashboard";
-import { createInstance, getUserSessions, startInstance, stopInstance, deleteInstance, recreateInstanceTunnel, type Session as SessionApi } from "../api/sessions";
+import { createInstance, getUserSessions, startInstance, stopInstance, deleteInstance, recreateInstanceTunnel, checkInstanceHealth, type Session as SessionApi, type InstanceHealth } from "../api/sessions";
 import { listProjects } from "../api/projects";
 import { listRepositories, type GitRepository } from "../api/git_repositories";
 import { listToolTypes, type ToolType } from "../api/tool_types";
@@ -34,6 +34,9 @@ export const HomePage = () => {
   const [displayName, setDisplayName] = useState("");
   const [saveState, setSaveState] = useState<"idle" | "saving" | "error">("idle");
   const [actionBusy, setActionBusy] = useState<string | null>(null);
+  const [stopConfirmId, setStopConfirmId] = useState<string | null>(null);
+  const [deleteConfirmId, setDeleteConfirmId] = useState<string | null>(null);
+  const [tunnelHealth, setTunnelHealth] = useState<Record<string, InstanceHealth>>({});
   const safeSessions = Array.isArray(sessions) ? sessions : [];
 
   const loadHome = useCallback(async () => {
@@ -59,6 +62,49 @@ export const HomePage = () => {
     void loadHome();
   }, [loadHome]);
 
+  // Poll tunnel health every 30 seconds for running instances
+  useEffect(() => {
+    const checkHealth = async () => {
+      const runningSessions = safeSessions.filter(
+        (s) => s.status === "running" && s.url
+      );
+      for (const session of runningSessions) {
+        try {
+          const health = await checkInstanceHealth(
+            session.project_id,
+            session.repository_id,
+            session.id
+          );
+          setTunnelHealth((prev) => ({
+            ...prev,
+            [session.id]: health,
+          }));
+        } catch {
+          setTunnelHealth((prev) => ({
+            ...prev,
+            [session.id]: {
+              healthy: false,
+              container_status: "unknown",
+              container_health: null,
+              container_exit_code: null,
+              tunnel_status: "error",
+              tunnel_status_code: null,
+              probe_status: "error",
+              last_probe_output: null,
+              error: "check failed",
+            },
+          }));
+        }
+      }
+    };
+
+    void checkHealth();
+    const interval = setInterval(() => {
+      void checkHealth();
+    }, 30000);
+    return () => clearInterval(interval);
+  }, [safeSessions]);
+
   useEffect(() => {
     if (!selectedProject) {
       setRepositories([]);
@@ -120,7 +166,12 @@ export const HomePage = () => {
   };
 
   const handleStop = async (session: SessionView) => {
+    if (stopConfirmId !== session.id) {
+      setStopConfirmId(session.id);
+      return;
+    }
     setActionBusy(session.id);
+    setStopConfirmId(null);
     try {
       await stopInstance(session.project_id, session.repository_id, session.id);
       await loadHome();
@@ -130,10 +181,17 @@ export const HomePage = () => {
   };
 
   const handleDelete = async (session: SessionView) => {
+    if (deleteConfirmId !== session.id) {
+      setDeleteConfirmId(session.id);
+      return;
+    }
     setActionBusy(session.id);
+    setDeleteConfirmId(null);
     try {
       await deleteInstance(session.project_id, session.repository_id, session.id);
-      await loadHome();
+      setSessions((prev) => prev.filter((s) => s.id !== session.id));
+    } catch {
+      // error - session remains in state
     } finally {
       setActionBusy(null);
     }
@@ -203,36 +261,65 @@ export const HomePage = () => {
               <p className="muted">No active sessions right now.</p>
             ) : (
               <div className="home-session-grid">
-                {activeSessions.map((session) => (
-                  <article className="card session-card" key={session.id}>
-                    <div className="stack-sm">
-                      <div className="row row-tight">
-                        <h3>{session.display_name}</h3>
-                        <span className={`status-badge ${session.status}`}>{session.status}</span>
+                {activeSessions.map((session) => {
+                  const health = tunnelHealth[session.id];
+                  const isUnhealthy = health && !health.healthy;
+                  return (
+                    <article className="card session-card" key={session.id}>
+                      <div className="stack-sm">
+                        <div className="row row-tight">
+                          <h3>{session.display_name}</h3>
+                          <div className="row row-tight">
+                            {isUnhealthy && (
+                              <span className="status-badge error" title={health.error || "unhealthy"}>!</span>
+                            )}
+                            <span className={`status-badge ${session.status}`}>{session.status}</span>
+                          </div>
+                        </div>
+                        <p className="muted">{session.project_name} · {session.repository_name}</p>
+                        <p className="muted">{session.tool_type_name}</p>
                       </div>
-                      <p className="muted">{session.project_name} · {session.repository_name}</p>
-                      <p className="muted">{session.tool_type_name}</p>
-                    </div>
-                    <div className="session-actions">
-                      <button className="secondary-button small" type="button" onClick={() => handleOpen(session)}>
-                        <Icon name="external" size="sm" />
-                        Open
-                      </button>
-                      <button className="ghost-button small" type="button" onClick={() => void handleRecreateTunnel(session)} disabled={actionBusy === session.id}>
-                        <Icon name="refresh" size="sm" />
-                        Tunnel
-                      </button>
-                      <button className="ghost-button small" type="button" onClick={() => void handleStop(session)} disabled={actionBusy === session.id}>
-                        <Icon name="stop" size="sm" />
-                        Stop
-                      </button>
-                      <button className="ghost-button small danger-text" type="button" onClick={() => void handleDelete(session)} disabled={actionBusy === session.id}>
-                        <Icon name="delete" size="sm" />
-                        Delete
-                      </button>
-                    </div>
-                  </article>
-                ))}
+                      <div className="session-actions">
+                        <button className="secondary-button small" type="button" onClick={() => handleOpen(session)}>
+                          <Icon name="external" size="sm" />
+                          Open
+                        </button>
+                        <button className="ghost-button small" type="button" onClick={() => void handleRecreateTunnel(session)} disabled={actionBusy === session.id}>
+                          <Icon name="refresh" size="sm" />
+                          Tunnel
+                        </button>
+                        {stopConfirmId === session.id ? (
+                          <div className="stop-confirm-inline">
+                            <span className="confirm-text">Stop?</span>
+                            <button className="ghost-button small danger-text" type="button" onClick={() => void handleStop(session)} disabled={actionBusy === session.id}>
+                              <Icon name="stop" size="sm" /> Stop
+                            </button>
+                            <button className="ghost-button small" type="button" onClick={() => setStopConfirmId(null)}>Cancel</button>
+                          </div>
+                        ) : (
+                          <button className="ghost-button small" type="button" onClick={() => void handleStop(session)} disabled={actionBusy === session.id}>
+                            <Icon name="stop" size="sm" />
+                            Stop
+                          </button>
+                        )}
+                        {deleteConfirmId === session.id ? (
+                          <div className="delete-confirm-inline">
+                            <span className="confirm-text">Delete?</span>
+                            <button className="ghost-button small danger-text" type="button" onClick={() => void handleDelete(session)} disabled={actionBusy === session.id}>
+                              <Icon name="delete" size="sm" /> Delete
+                            </button>
+                            <button className="ghost-button small" type="button" onClick={() => setDeleteConfirmId(null)}>Cancel</button>
+                          </div>
+                        ) : (
+                          <button className="ghost-button small danger-text" type="button" onClick={() => void handleDelete(session)} disabled={actionBusy === session.id}>
+                            <Icon name="delete" size="sm" />
+                            Delete
+                          </button>
+                        )}
+                      </div>
+                    </article>
+                  );
+                })}
               </div>
             )}
           </section>

apps/web/src/router.tsx

@@ -16,12 +16,12 @@ import { ToolWorkshopPage } from "./pages/tool-workshop";
 import { SSHKeysPage } from "./pages/ssh-keys";
 import { ToolConfigsPage } from "./pages/tool-configs";
 import { ToolTypesPage } from "./pages/tool-types";
+import { SessionsPage } from "./pages/sessions";
 
 export const AppRouter = () => {
   return (
     <Routes>
       <Route path="/login" element={<LoginRedirectPage />} />
-      <Route path="/sessions" element={<Navigate to="/" replace />} />
       <Route path="/ssh-keys" element={<Navigate to="/settings/ssh-keys" replace />} />
       <Route path="/tool-types" element={<Navigate to="/settings/tool-types" replace />} />
       <Route path="/tool-configs" element={<Navigate to="/settings/tool-configs" replace />} />
@@ -48,6 +48,7 @@ export const AppRouter = () => {
           <Route path="tool-configs" element={<ToolConfigsPage />} />
           <Route path="*" element={<Navigate to="general" replace />} />
         </Route>
+        <Route path="sessions" element={<SessionsPage />} />
         <Route path="tool-workshop" element={<ToolWorkshopPage />} />
         <Route path="instances/:instanceId/terminal" element={<TerminalPage />} />
       </Route>