Register console up/down history keybindings

[juliasilge]

Fixes #13419

The console's keyDownHandler in consoleInput.tsx currently intercepts arrow keys at the React layer before the keybinding service can see them. The UpArrow / DownArrow cases match on KeyCode alone, so Shift+Down and Shift+Up route to history navigation instead of falling through to cursorDownSelect / cursorUpSelect, breaking text selection.

This PR migrates Up/Down and Cmd/Ctrl+Up history navigation out of the React switch and into proper Action2 keybindings:

• NavigateInputHistoryUp (Up)
• NavigateInputHistoryDown (Down)
• NavigateInputHistoryUpUsingPrefixMatch (Cmd/Ctrl+Up)

All three actions already existed (invokable from the Command Palette) but had no keybinding block. Adding the keybindings (a) fixes #13419 because Shift+Down no longer matches primary: KeyCode.DownArrow, letting the editor's cursorDownSelect win on weight, (b) surfaces the bindings in the Keyboard Shortcuts UI (addresses part of #7380), and (c) lets user-defined keybindings override them.

A new context key positronConsoleInputCursorBoundary (mirroring upstream's INTERACTIVE_INPUT_CURSOR_BOUNDARY) gates the keybindings so the action only fires when the cursor is at the appropriate boundary of the console input. Without this gate, the registered keybinding would steal Up/Down on interior lines of multi-line input.

This also fixes a pre-existing inconsistency where the prefix-match history browser was filtering by debug mode when invoked from Cmd/Ctrl+Up but not when invoked from the Command Palette. Both paths now filter consistently.

This is the first in a planned series of console keybinding migrations to address #7380 and related problems like #9500.

Release Notes

New Features

• N/A

Bug Fixes

• Fix Shift+Down and Shift+Up in the console to extend text selection instead of triggering history navigation (Shift+Down and Shift+Up in console trigger history navigation instead of extending text selection #13419)

Validation Steps

@:console @:web @:win

New e2e regression tests cover the primary fixes:

• 'Python - Shift+Down extends selection instead of navigating history'
• 'Python - Cmd+Up engages prefix-match history browser'

Manual checks, for example during review:

1. In an R or Python console, type some text on a single line. Place the cursor mid-text and press Shift+Down: the selection should extend to the end of the line, and typing should replace the selected text.
2. Press Up and Down arrows with no modifiers: history navigation works as before.
3. Type a prefix, press Cmd/Ctrl+Up: the prefix-match history browser engages, filtering to entries matching the prefix.
4. With multi-line input (use Shift+Enter for the second line), place cursor on an interior line and press Up: cursor moves up within the input rather than triggering history navigation.
5. With autocomplete visible, Up/Down should navigate suggestions, not history.
6. Open the Keyboard Shortcuts UI and search "Navigate Input History": the three migrated actions display their bindings like so:

[github-actions]

E2E Tests 🚀
This PR will run tests tagged with: @:critical @:console @:web @:win

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