Add SQLite-backed announcement system and admin portal

- Add SQLite database initialization and management in inc/db.php
- Implement session authentication and CSRF security helpers in inc/auth.php
- Implement announcement querying and saving in inc/announcements.php
- Add management dashboard, login, and logout in admin/
- Protect db/ directory with Apache access controls

inc/db.php

@@ -0,0 +1,82 @@
+<?php
+/**
+ * Database connection & schema management for SQLite
+ */
+
+function get_db(): PDO {
+    static $pdo = null;
+    if ($pdo !== null) {
+        return $pdo;
+    }
+
+    $dbDir = __DIR__ . '/../db';
+    if (!is_dir($dbDir)) {
+        mkdir($dbDir, 0755, true);
+    }
+
+    $dbPath = $dbDir . '/fitz.sqlite';
+    $isNew = !file_exists($dbPath);
+
+    $pdo = new PDO('sqlite:' . $dbPath, null, null, [
+        PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,
+        PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC,
+        PDO::ATTR_TIMEOUT => 5
+    ]);
+
+    // Enable WAL mode for concurrency and performance
+    $pdo->exec('PRAGMA journal_mode = WAL;');
+    $pdo->exec('PRAGMA foreign_keys = ON;');
+
+    // Initialize tables if needed
+    init_db_schema($pdo);
+
+    return $pdo;
+}
+
+function init_db_schema(PDO $pdo): void {
+    $pdo->exec("
+        CREATE TABLE IF NOT EXISTS users (
+            id INTEGER PRIMARY KEY AUTOINCREMENT,
+            username TEXT UNIQUE NOT NULL,
+            password_hash TEXT NOT NULL,
+            role TEXT NOT NULL DEFAULT 'admin',
+            created_at DATETIME DEFAULT CURRENT_TIMESTAMP
+        );
+
+        CREATE TABLE IF NOT EXISTS announcements (
+            id INTEGER PRIMARY KEY AUTOINCREMENT,
+            is_active INTEGER NOT NULL DEFAULT 1,
+            type TEXT NOT NULL DEFAULT 'holiday',
+            headline TEXT NOT NULL,
+            message TEXT NOT NULL,
+            start_date TEXT NULL,
+            end_date TEXT NULL,
+            show_banner INTEGER NOT NULL DEFAULT 1,
+            show_in_hours INTEGER NOT NULL DEFAULT 1,
+            updated_at DATETIME DEFAULT CURRENT_TIMESTAMP
+        );
+    ");
+
+    // Seed default admin user if table is empty (username: admin / password: password)
+    $stmt = $pdo->query("SELECT COUNT(*) as count FROM users");
+    $userCount = $stmt->fetchColumn();
+    if ($userCount == 0) {
+        $defaultPassHash = password_hash('password', PASSWORD_DEFAULT);
+        $insert = $pdo->prepare("INSERT INTO users (username, password_hash, role) VALUES (?, ?, 'admin')");
+        $insert->execute(['admin', $defaultPassHash]);
+    }
+
+    // Seed default Labor Day announcement row if table is empty
+    $stmtAnn = $pdo->query("SELECT COUNT(*) as count FROM announcements");
+    $annCount = $stmtAnn->fetchColumn();
+    if ($annCount == 0) {
+        $insertAnn = $pdo->prepare("
+            INSERT INTO announcements (
+                is_active, type, headline, message, start_date, end_date, show_banner, show_in_hours
+            ) VALUES (
+                1, 'holiday', 'Labor Day Closure', 'The Old Fitz will be closed Thursday, Sept 3 through Saturday, Sept 5 for the holiday weekend. Doors reopen Thursday, Sept 10 at 4:00 PM!', NULL, NULL, 1, 1
+            )
+        ");
+        $insertAnn->execute();
+    }
+}