Migrate the conversation summary App Server methods to ThreadStore
Because this app server api allows explicitly fetching the thread by
rollout path, intercept that case in the app server code and (a) route
directly to underlying local thread store methods if we're using a local
thread store, or (b) throw an unsupported error if we're using a remote
thread store. This keeps the thread store API clean and all filesystem
operations inside of the local thread store, which pushing the
"fundamental incompatibility" check as early as possible.
Summary
- replace the thread/read persisted-load helper with
ThreadStore::read_thread
- move SQLite/rollout summary, name, fork metadata, and history loading
for persisted reads into LocalThreadStore
- leave getConversationSummary unchanged for a later PR
Context
- Replaces closed stacked PR #18232 after PR #18231 merged and its base
branch was deleted.
# Summary
- implement local ThreadStore archive/unarchive operations
- implement local ThreadStore read_thread operation
- break up the various ThreadStore local method implementations into
separate files
- migrate app-server archive/unarchive and core archive fixture to use
ThreadStore (but not all read operations yet!)
- use the ThreadStore's read operation as a proxy check for thread
persistence/existence in the app server code
- move all other filesystem operations related to archive (path
validation etc) into the local thread store.
# Tests
- add dedicated local store archive/unarchive tests
