* fix(web): recalculate dockview layout after fast-path session switch
The fast path in tryFastSessionSwitch removed ephemeral panels but
never called api.layout() to redistribute column widths, leaving a
gap on the right side of the screen. Both slow-path branches already
make this call.
* test(web): add regression test for fast-path layout call
Verifies that performSessionSwitch calls api.layout() on both the
fast path and slow path, preventing the squished-layout regression.
* test(web): cover saved-layout fast path branch
* fix(web): replace no-explicit-any cast in test
* fix(web): fix test isolation with mockReturnValueOnce
Use mockReturnValueOnce and clearAllMocks for proper test isolation
between fast-path and slow-path test cases.
* test(web): fix mock shape to match LayoutGroupIds type
José Almeida
2872d072cb