feat(auth): guest login with random telegraph operator name

No email required — players pick male/female/mystery, get assigned
a humorous period-appropriate operator name (e.g. "Dusty Clicksworth",
"Ada Dottsworth", "The Phantom Sender"), can reroll, then hit
"Begin Transmitting!" for instant play. Email/magic link moved to
a collapsible section for cross-device access only.

- server: POST /api/auth/guest creates guest profile + session
- server/db: profiles.email now nullable, is_guest column added,
  migration recreates table for existing installs
- client: names.ts with 15 names per gender category
- client: LoginPage redesigned — gender picker → name display → play
- client: useAuth gains setAuth() for direct session injection
- 55 server + 44 client tests pass

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

server/db.js

@@ -8,11 +8,33 @@ function initDb(dbPath) {
   instance.pragma('journal_mode = WAL')
   instance.pragma('foreign_keys = ON')
 
+  // Migration: add is_guest + make email nullable on existing installs
+  const profileCols = instance.pragma('table_info(profiles)').map(c => c.name)
+  if (profileCols.length > 0 && !profileCols.includes('is_guest')) {
+    instance.pragma('foreign_keys = OFF')
+    instance.exec(`
+      CREATE TABLE profiles_v2 (
+        id INTEGER PRIMARY KEY AUTOINCREMENT,
+        email TEXT UNIQUE,
+        display_name TEXT,
+        is_guest INTEGER NOT NULL DEFAULT 0,
+        created_at INTEGER NOT NULL,
+        last_seen INTEGER NOT NULL
+      );
+      INSERT INTO profiles_v2 (id, email, display_name, is_guest, created_at, last_seen)
+        SELECT id, email, display_name, 0, created_at, last_seen FROM profiles;
+      DROP TABLE profiles;
+      ALTER TABLE profiles_v2 RENAME TO profiles;
+    `)
+    instance.pragma('foreign_keys = ON')
+  }
+
   instance.exec(`
     CREATE TABLE IF NOT EXISTS profiles (
       id           INTEGER PRIMARY KEY AUTOINCREMENT,
-      email        TEXT UNIQUE NOT NULL,
+      email        TEXT UNIQUE,
       display_name TEXT,
+      is_guest     INTEGER NOT NULL DEFAULT 0,
       created_at   INTEGER NOT NULL,
       last_seen    INTEGER NOT NULL
     );
@@ -56,6 +78,13 @@ function initDb(dbPath) {
     );
   `)
 
+  function createGuestProfile(displayName) {
+    const now = Date.now()
+    return instance.prepare(
+      'INSERT INTO profiles (email, display_name, is_guest, created_at, last_seen) VALUES (NULL,?,1,?,?) RETURNING *'
+    ).get(displayName, now, now)
+  }
+
   function createProfile(email, displayName) {
     const now = Date.now()
     const stmt = instance.prepare(
@@ -230,6 +259,7 @@ function initDb(dbPath) {
 
   return {
     _db: instance,
+    createGuestProfile,
     createProfile,
     findProfileByEmail,
     findProfileById,