[datlechin]

Summary

• Two to six results show as tabs in a bar above the grid, one click per switch. One result keeps the status-bar pull-down; more than six, or a pane too narrow for the names, keeps only the pull-down.
• The tabs are an NSSegmentedControl, with the tabs role on macOS 27. Measured on 27.0.1: SwiftUI's segmented and .tabs pickers drop a segment's image, so the pin glyph on a pinned tab needs AppKit.
• The result pull-down moves to the end of the tab row and keeps the list, Pin, Compare, Close and Close Others. No stock control reports which segment was right-clicked (setMenu(_:forSegment:) ignores right-click, there is no segment hit test), so there is no per-tab context menu.
• Two results from one table read users and users (2). The pull-down title is a position, 2 of 4, and the comparison titles use the result names. ResultSetMenuModelTests.titleCountsResults changes from Result 2 of 4 to 2 of 4 on purpose.
• Fixed in the code this touches:
  • Closing the active result selected the last result; it now selects the neighbour, as editor tabs do.
  • Close, Close Others and Clear Results dropped unsaved cell edits without asking. They now ask, each with its own wording.
  • Close Others ran one close per result in the view. It is now one coordinator operation that activates the kept result.
  • View > Close Result Tab blanked a table tab's rows, and Previous/Next/Close Result stayed enabled with nothing to do, in Agent mode too.
  • Dismissing an Error result's banner turned the result into "Query executed successfully". That banner now has no Dismiss: the message is the result.
  • A failed script copied its error onto the tab, so the banner sat over every result that succeeded. The error and its SQL now live on the Error result, and Fix with AI and /fix still find it.
  • Result names were cut inside an emoji (U+FFFD).
  • A new run numbered its results from 1 even with pinned results in front, repeating a pinned result's name.
• The error banner's message gives way down to one line in a short pane, so the tab row and the status bar stay inside the 150pt minimum.

Test plan

• New: ResultSetTabBarLayoutTests (tabs, fallback, more than six, pin and selection, width, 150pt pane), ScriptErrorResultTests (a failed script through the coordinator), close/close others/gate/menu-flag cases in ResultPinningTests, placement and error-precedence cases in QueryResultPresentationTests, ResultSetPolicyTests over 2 to 8 results, emoji truncation in ResultSetMenuModelTests and StatementAnchorTests.
• QueryRunUITests clicks a result tab and checks the switch.

Fixes #3869

[datlechin]

Before and after, three results with the last one pinned.

	Before	After
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