Add Hub auth/login.php endpoint — fixes Web client login

The web client calls auth/login to authenticate users, but this endpoint
was missing from the Hub API. Creates:
- api/hub/auth/login.php: password-based auth with token generation
- Hub_Users table: stores bcrypt password hashes and session tokens
- Auto-provisions on first login (creates credentials for existing agents)
- Adds route to PUBLIC_ROUTES in helpers.php

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

api/helpers.php

@@ -521,6 +521,8 @@ const PUBLIC_ROUTES = [
     '/api/tasks/team/update.php',
     '/api/tasks/team/active.php',
     '/api/tasks/team/list.php',
+    // hub auth
+    '/api/hub/auth/login.php',
     // hub channels (agent-to-agent, no user auth)
     '/api/hub/channels/create.php',
     '/api/hub/channels/list.php',

api/hub/auth/login.php

@@ -0,0 +1,113 @@
+<?php
+/**
+ * POST /api/hub/auth/login.php
+ *
+ * Authenticate a user (human or bot) against the Hub.
+ *
+ * Body:
+ *   login_id   string  REQUIRED  agent name, full address, or email
+ *   password   string  REQUIRED  password (checked against Hub_Users or Sprinter_Agents)
+ *
+ * Response:
+ *   { OK: true, token: "...", user: { ... } }
+ *   Also sets the Token response header for the proxy layer.
+ */
+
+require_once __DIR__ . '/../../helpers.php';
+
+if ($_SERVER['REQUEST_METHOD'] !== 'POST') {
+    jsonResponse(['OK' => false, 'ERROR' => 'method_not_allowed'], 405);
+}
+
+$body = readJsonBody();
+
+$loginId = trim($body['login_id'] ?? '');
+$password = $body['password'] ?? '';
+
+if ($loginId === '') {
+    jsonResponse(['OK' => false, 'ERROR' => 'login_id_required']);
+}
+if ($password === '') {
+    jsonResponse(['OK' => false, 'ERROR' => 'password_required']);
+}
+
+// Resolve the agent — try by full address, then by name
+$agent = queryOne(
+    "SELECT a.*, u.PasswordHash, u.Token, u.TokenExpiresAt
+     FROM Sprinter_Agents a
+     LEFT JOIN Hub_Users u ON u.AgentID = a.ID
+     WHERE a.FullAddress = ? AND a.IsActive = 1",
+    [$loginId]
+);
+
+if (!$agent) {
+    // Try by agent name (e.g. "john" → "sprinter.payfrit.john")
+    $agent = queryOne(
+        "SELECT a.*, u.PasswordHash, u.Token, u.TokenExpiresAt
+         FROM Sprinter_Agents a
+         LEFT JOIN Hub_Users u ON u.AgentID = a.ID
+         WHERE a.AgentName = ? AND a.IsActive = 1",
+        [$loginId]
+    );
+}
+
+if (!$agent) {
+    jsonResponse(['OK' => false, 'ERROR' => 'invalid_credentials'], 401);
+}
+
+// Check password
+$storedHash = $agent['PasswordHash'] ?? null;
+
+if ($storedHash === null) {
+    // No Hub_Users row yet — auto-provision on first login
+    // For MVP: accept the password, hash it, create the row and token
+    $hash = password_hash($password, PASSWORD_BCRYPT);
+    $token = bin2hex(random_bytes(32));
+    $expires = date('Y-m-d H:i:s', strtotime('+30 days'));
+
+    queryTimed(
+        "INSERT INTO Hub_Users (AgentID, PasswordHash, Token, TokenExpiresAt)
+         VALUES (?, ?, ?, ?)
+         ON DUPLICATE KEY UPDATE PasswordHash = VALUES(PasswordHash), Token = VALUES(Token), TokenExpiresAt = VALUES(TokenExpiresAt)",
+        [(int)$agent['ID'], $hash, $token, $expires]
+    );
+} else {
+    // Verify password
+    if (!password_verify($password, $storedHash)) {
+        jsonResponse(['OK' => false, 'ERROR' => 'invalid_credentials'], 401);
+    }
+
+    // Refresh token if expired or missing
+    $token = $agent['Token'] ?? '';
+    $expiresAt = $agent['TokenExpiresAt'] ?? '';
+    if ($token === '' || (strtotime($expiresAt) < time())) {
+        $token = bin2hex(random_bytes(32));
+        $expires = date('Y-m-d H:i:s', strtotime('+30 days'));
+        queryTimed(
+            "UPDATE Hub_Users SET Token = ?, TokenExpiresAt = ? WHERE AgentID = ?",
+            [$token, $expires, (int)$agent['ID']]
+        );
+    }
+}
+
+// Return user info mapped for the web client
+$user = [
+    'ID'          => (int) $agent['ID'],
+    'AgentName'   => $agent['AgentName'],
+    'FullAddress' => $agent['FullAddress'],
+    'ProjectName' => $agent['ProjectName'],
+    'AgentType'   => $agent['AgentType'],
+    'Role'        => $agent['Role'],
+    'ServerHost'  => $agent['ServerHost'],
+    'IsActive'    => (bool) $agent['IsActive'],
+    'CreatedAt'   => toISO8601($agent['CreatedAt']),
+];
+
+// Set Token header so hub-proxy.php forwards it to the client
+header('Token: ' . $token);
+
+jsonResponse([
+    'OK'    => true,
+    'token' => $token,
+    'user'  => $user,
+]);