Update contact subject dropdown to match actual services; update README

Contact form subject options now match the five service lines on the site:
New Project Inquiry, Mesh Networking, Managed Services, Structured
Cabling, Access Control, IP Camera Systems, Technical Support, Other.
Removed the old ISP-generic options (billing, coverage, new-service).
Updated $subject_labels in admin-inbox.php to match.

README updates:
- ADMIN_PASS added to web container env vars table and env vars section
- Project structure updated to include db.php and admin-inbox.php
- Milestone 1 contact form item updated to note MySQL storage
- Milestone 4 marks contact DB storage and staff inbox as complete;
  email notification remains as the next open item

https://claude.ai/code/session_015wpwmheufcxkBuXivrSHhd

www/pages/admin-inbox.php

@@ -101,11 +101,14 @@ $messages    = $db->query("SELECT * FROM contacts ORDER BY created_at DESC")->fe
 $unread_count = (int)$db->query("SELECT COUNT(*) FROM contacts WHERE is_read = 0")->fetchColumn();
 
 $subject_labels = [
-    'new-service' => 'New Service Inquiry',
-    'support'     => 'Technical Support',
-    'billing'     => 'Billing Question',
-    'coverage'    => 'Coverage Question',
-    'other'       => 'Other',
+    'new-project'       => 'New Project Inquiry',
+    'mesh-networking'   => 'Mesh Networking',
+    'managed-services'  => 'Managed Services',
+    'structured-cabling'=> 'Structured Cabling',
+    'access-control'    => 'Access Control',
+    'ip-cameras'        => 'IP Camera Systems',
+    'support'           => 'Technical Support',
+    'other'             => 'Other',
 ];
 
 function h(string $s): string { return htmlspecialchars($s, ENT_QUOTES); }

www/pages/contact.php

@@ -88,10 +88,13 @@ if ($_SERVER['REQUEST_METHOD'] === 'POST') {
                         <label for="subject" class="form__label">Subject</label>
                         <select id="subject" name="subject" class="form__input">
                             <option value="">Select a topic…</option>
-                            <option value="new-service">New Service Inquiry</option>
+                            <option value="new-project">New Project Inquiry</option>
+                            <option value="mesh-networking">Mesh Networking</option>
+                            <option value="managed-services">Managed Services</option>
+                            <option value="structured-cabling">Structured Cabling</option>
+                            <option value="access-control">Access Control</option>
+                            <option value="ip-cameras">IP Camera Systems</option>
                             <option value="support">Technical Support</option>
-                            <option value="billing">Billing Question</option>
-                            <option value="coverage">Coverage Question</option>
                             <option value="other">Other</option>
                         </select>
                     </div>