fix(status-bar): 'Running query…' stays after a successful SELECT (plain row-count status line) #1556

Problem

After a successful SELECT the status bar keeps showing "Running query…" until the next query. It is stuck, not just late: seen 4 s after the grid had been shown.

Cause

GenericSqlWorkspace publishes the result with message: _shellMessage(session.statusLine), and _shellMessage deliberately returns null for a plain "N row(s)." status line (the counts are already on the right of the bar). QueryaShellStatus.reportQueryResult then does:

if (message != null) _statusMessage = message;   // null: keeps the old "Running query…"
_messageIsBusy = false;                          // ...and now it is no longer dropped by endBusy()

So the busy message set by beginBusy survives and is re-labelled as a normal message.

Reproduction

Demo Playground -> SQL -> SELECT * FROM orders LIMIT 200; -> F5. The grid shows 12 rows, the bar shows Running query…, 1 ms, 12 rows, 8 cols.

Fix

In reportQueryResult, take the message as given (_statusMessage = message;), or drop the busy message when message == null (if (_messageIsBusy) _statusMessage = null before the assignment). Add a unit test: beginBusy(message: 'Running query…') then reportQueryResult(message: null) leaves statusMessage == null.

Acceptance

• Plain-count results leave no message in the bar.
• Results with a script / affected-rows status still show their text.
• Unit test for the sequence above.

Related: #714 (live status-bar metrics), #1481.