chore: remove deprecated demo make target and update attachment thumbnail resolution

- Remove `make demo` target from Makefile, AGENTS.md, and README.md
- Improve `_row_to_attachment` to glob for thumbnail files with any extension instead of hardcoding `.jpg`
- Rewrite `cmd_attachments_prune` to use time-based cutoff and `delete_attachment` helper instead of orphan detection
- Add cursor-based pagination to feed and notifications endpoints with `before` parameter
- Track `did_upvote` flag in vote handler to only notify on new upvotes, not vote changes
- Add `PAGE_SIZE` constant and `next_cursor` template variable to notifications page
- Implement Playwright tests for notification pagination with 30 seeded notifications

tests/test_notifications.py

@@ -1,4 +1,69 @@
+from datetime import datetime, timedelta, timezone
 from tests.conftest import BASE_URL
+from devplacepy.database import get_table
+from devplacepy.utils import generate_uid
+
+
+def test_notifications_pagination(alice):
+    page, _ = alice
+    alice_row = get_table("users").find_one(username="alice_test")
+    notifications_table = get_table("notifications")
+    notifications_table.delete(user_uid=alice_row["uid"])
+
+    now = datetime.now(timezone.utc)
+    for i in range(30):
+        notifications_table.insert({
+            "uid": generate_uid(),
+            "user_uid": alice_row["uid"],
+            "type": "test",
+            "message": f"pagination-test-msg-{i:02d}",
+            "related_uid": alice_row["uid"],
+            "target_url": "/feed",
+            "read": False,
+            "created_at": (now - timedelta(seconds=i)).isoformat(),
+        })
+
+    page.goto(f"{BASE_URL}/notifications", wait_until="domcontentloaded")
+    cards = page.locator(".notification-card")
+    assert cards.count() == 25, f"expected 25 cards on page 1, got {cards.count()}"
+
+    load_more = page.locator(".load-more-wrap a")
+    load_more.wait_for(state="visible", timeout=5000)
+    href = load_more.get_attribute("href")
+    assert href and "before=" in href, f"Load More should carry cursor: {href}"
+
+    page.goto(f"{BASE_URL}{href}", wait_until="domcontentloaded")
+    cards2 = page.locator(".notification-card")
+    assert cards2.count() == 5, f"expected 5 cards on page 2, got {cards2.count()}"
+    assert page.locator(".load-more-wrap").count() == 0, "Load More should be absent on final page"
+
+    notifications_table.delete(user_uid=alice_row["uid"])
+
+
+def test_notifications_no_load_more_when_under_page_size(alice):
+    page, _ = alice
+    alice_row = get_table("users").find_one(username="alice_test")
+    notifications_table = get_table("notifications")
+    notifications_table.delete(user_uid=alice_row["uid"])
+
+    now = datetime.now(timezone.utc)
+    for i in range(3):
+        notifications_table.insert({
+            "uid": generate_uid(),
+            "user_uid": alice_row["uid"],
+            "type": "test",
+            "message": f"small-set-msg-{i}",
+            "related_uid": alice_row["uid"],
+            "target_url": "/feed",
+            "read": False,
+            "created_at": (now - timedelta(seconds=i)).isoformat(),
+        })
+
+    page.goto(f"{BASE_URL}/notifications", wait_until="domcontentloaded")
+    assert page.locator(".notification-card").count() == 3
+    assert page.locator(".load-more-wrap").count() == 0
+
+    notifications_table.delete(user_uid=alice_row["uid"])
 
 
 def test_notifications_page_loads(alice):