Initial plugin scaffold: lesson scheduling WordPress plugin

- Custom DB tables for availability slots and lesson bookings
- Instructor (wp-admin) and student (front-end) roles with custom capabilities
- REST API under us-scheduler/v1 for availability CRUD and booking
- [us_booking] and [us_student_login] shortcodes for student front end
- PHPUnit + Brain\Monkey unit test suite (29 tests)
- Gitea Actions CI: lint, PHPStan, tests on PHP 8.1/8.2/8.3, no-debug check
- Feature docs under docs/features/

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

src/Data/AvailabilityRepository.php

@@ -0,0 +1,117 @@
+<?php
+declare(strict_types=1);
+
+namespace Unsupervised\Schedular\Data;
+
+use Unsupervised\Schedular\Model\AvailabilitySlot;
+
+class AvailabilityRepository
+{
+    private string $table;
+
+    public function __construct(private \wpdb $db)
+    {
+        $this->table = $db->prefix . 'us_availability';
+    }
+
+    public function insert(AvailabilitySlot $slot): int
+    {
+        $this->db->insert(
+            $this->table,
+            [
+                'instructor_id' => $slot->instructorId,
+                'start_dt'      => $slot->startDt,
+                'end_dt'        => $slot->endDt,
+                'is_booked'     => 0,
+                'created_at'    => current_time('mysql'),
+            ],
+            ['%d', '%s', '%s', '%d', '%s']
+        );
+
+        return $this->db->insert_id;
+    }
+
+    /**
+     * Find unbooked slots, optionally filtered by instructor and date range.
+     *
+     * @return list<AvailabilitySlot>
+     */
+    public function findAvailable(int $instructorId = 0, string $from = '', string $to = ''): array
+    {
+        $where  = ['is_booked = 0'];
+        $params = [];
+
+        if ($instructorId > 0) {
+            $where[]  = 'instructor_id = %d';
+            $params[] = $instructorId;
+        }
+
+        if ($from !== '') {
+            $where[]  = 'start_dt >= %s';
+            $params[] = $from;
+        }
+
+        if ($to !== '') {
+            $where[]  = 'end_dt <= %s';
+            $params[] = $to;
+        }
+
+        $whereClause = implode(' AND ', $where);
+        $sql         = "SELECT * FROM {$this->table} WHERE {$whereClause} ORDER BY start_dt ASC";
+
+        $rows = $params
+            ? $this->db->get_results($this->db->prepare($sql, $params))
+            : $this->db->get_results($sql);
+
+        return array_map(AvailabilitySlot::fromRow(...), $rows ?? []);
+    }
+
+    /**
+     * Find all slots for an instructor (booked and unbooked).
+     *
+     * @return list<AvailabilitySlot>
+     */
+    public function findByInstructor(int $instructorId): array
+    {
+        $rows = $this->db->get_results(
+            $this->db->prepare(
+                "SELECT * FROM {$this->table} WHERE instructor_id = %d ORDER BY start_dt ASC",
+                $instructorId
+            )
+        );
+
+        return array_map(AvailabilitySlot::fromRow(...), $rows ?? []);
+    }
+
+    public function findById(int $id): ?AvailabilitySlot
+    {
+        $row = $this->db->get_row(
+            $this->db->prepare("SELECT * FROM {$this->table} WHERE id = %d", $id)
+        );
+
+        return $row ? AvailabilitySlot::fromRow($row) : null;
+    }
+
+    public function markBooked(int $id): bool
+    {
+        return (bool) $this->db->update(
+            $this->table,
+            ['is_booked' => 1],
+            ['id' => $id],
+            ['%d'],
+            ['%d']
+        );
+    }
+
+    /**
+     * Delete an unbooked slot. Returns false if the slot is already booked.
+     */
+    public function delete(int $id): bool
+    {
+        return (bool) $this->db->delete(
+            $this->table,
+            ['id' => $id, 'is_booked' => 0],
+            ['%d', '%d']
+        );
+    }
+}