ADR-0052 moved success journaling out of the worker to the dispatch
layer, leaving the `source` that handlers threaded purely for the
worker's old history.log write dead. Remove it:
- drop `_source` from finalize_persistence and do_rebuild_from_text
- inline + delete the three read-only *_request wrappers
- drop the now-unused `source` param from the ~30 forwarding worker
handlers (leaf + composite), compiler-guided
- remove the `source` field from the DescribeTable/QueryData/RunSelect
requests and their DatabaseHandle methods (call sites updated)
The only worker `source` left is the snapshot/undo label
(snapshot_then / stage_pre_mutation / begin_batch). Purely mechanical,
no behaviour change. 2471 pass / 0 fail / 1 ignored, clippy clean.
claude@clouddev1
e8fa859ab9