perf: optimize loading messages in threads (#552)

* perf: improve lazy loading and remove spinner

* perf: optimize message loading by caching and reducing queries

* docs: update changelog

* style: use constant for cache size

* refactor: minor consistency improvement

* fix: override loaded preview size

* refactor: streamline message loading logic in scroll listener

* refactor: organize some dedup related code

* build: bump detekt return count limit

2 is 2 low

* fix: check contacts permissions before registering observer

* fix: disable fetching media resolutions in threads

* refactor: remove resolution fetching related code

* perf: cache MMS thread participants

* refactor: remove unused BitmapFactory import

* fix: invalidate participants cache when necessary

* fix: return copied participants from cache

* fix: adjust image loading dimensions in threads

* fix: use stable ids for header items

* fix: always rely on database check before flipping `allMessagesFetched`

CHANGELOG.md

@@ -5,6 +5,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased]
+### Changed
+- Optimized loading messages in conversations
 
 ## [1.4.0] - 2025-10-12
 ### Added