Refactor pagination with cursor-based support and standardized response format

- Implement cursor-based pagination in pagination.py
- Update response models to standardize pagination structure
- Add cursor pagination utilities for repositories
- Update HistoryArchiveRepository and ImportLogRepository with new pagination
- Add comprehensive tests for cursor pagination
- Update documentation for backend development and task tracking

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Docs/Tasks.md

@@ -1,39 +1,3 @@
-## [IMPORTANT] Promise cancellation not checked in .then()/.catch() chains
-
-**Where found**
-
-- `frontend/src/components/blocklist/BlocklistSourcesSection.tsx:84-88`
-- `frontend/src/components/blocklist/BlocklistScheduleSection.tsx:49-58`
-- Multiple components use this pattern
-
-**Why this is needed**
-
-When user navigates away, `.then()` chains don't check if cancelled. State updated on unmounted component → React warnings, memory leak, notification shows wrong context.
-
-**Goal**
-
-Check for cancellation in all `.then()/.catch()` chains.
-
-**What to do**
-
-1. Replace `.then()/.catch()` with `async/await` and cancellation check
-2. Or use wrapper hook to hide logic
-
-**Possible traps and issues**
-
-- Checking `signal.aborted` after `await` introduces race conditions
-- Better: let AbortError propagate, catch it in catch block
-
-**Docs changes needed**
-
-- Update `Docs/Web-Development.md` § Async Patterns
-
-**Doc references**
-
-- `Docs/Web-Development.md` (async patterns)
-
----
-
 ## [MEDIUM] Inefficient database pagination uses OFFSET
 
 **Where found**