Keep each collection's response history to itself

[MathiasWP]

Hunting the same shape as the selection bug — an identifier assumed unique that isn't — by writing probes that assert the correct behaviour and letting the failures name the bugs.

Five probes over two collections describing one API. Two failed, and both were the same bug.

Found: history is shared between collections

Bucketed by request id alone, and a loaded endpoint's id is METHOD /path in every collection describing that API. So:

• Sending in staging, then opening production, showed staging's response under production.
• Both sends landed in one bucket, so clearing one cleared the other — including from disk, since clear_request matched on request_id.

Fix

Most of it was already there: the database has stored section_id since the column was added and simply never returned it. Selecting it onto HistoryRecord is enough for the window to tell the two apart. clear_request takes an optional section; unscoped still means everywhere, which is what scratch needs.

Old entries match any collection rather than vanishing — nothing knows where they came from, and dropping them would read as history lost. A scoped clear takes them too: they're the same request's older entries, and leaving them behind would look like the clear half-worked.

Passed, and kept

• Editing a body in one collection doesn't change the other (overlay is section-scoped).
• Forgetting an orphaned endpoint in one leaves the other's.
• Opening an endpoint asks for its own collection's schema.

They cost nothing and they're what would notice if any of those stopped being section-scoped.

On the probes themselves

Two early drafts passed by taking an if around a context-menu item that doesn't exist for loaded rows — a test that asserts nothing when its branch isn't taken is worse than no test. Both were rewritten to be unconditional, and there are no skips.

Verified the way the last one had to be: reverting the filter fails the probe.

Testing

cargo fmt --check, cargo clippy --no-default-features --all-targets -- -D warnings, cargo test (137 passed), pnpm check (0 errors), pnpm test:e2e (328 passed, 5 new).