[HarryCordewener]

Summary

Fixes #124.

SharpMUSH asks for physical cell pixels with CSI 16 t. Without a response it falls back to assumed cell proportions, so server-specified image boxes can stretch in the desktop renderer. This change supplies measured host geometry through TNC's opt-in terminal-query plugin.

• Opt into TerminalQueryProtocol.WithCellSizeProvider; TNC owns parsing, control-string shielding, replies and refresh ordering. No client-owned CSI parser or generic byte hook.
• Publish actual Avalonia font cell pixels through a dedicated ClientHost metrics channel, independent of pointer presentation.
• Refresh interested peers after zoom, display-scale changes, and connection completion, including changes that leave the character grid unchanged.
• In Unix terminal mode, read published terminal pixel extents through ioctl without reading terminal input; poll for pixel-only changes and stop on shutdown. Missing, invalid or inexact measurements remain unknown. Windows pseudoconsole metrics remain unknown rather than reporting a virtual console's misleading font size.
• Update TelnetNegotiationCore to released NuGet 4.9.0, containing Add opt-in client terminal cell-size responder HarryCordewener/TelnetNegotiationCore#182. No SharpConsoleUI changes.

Validation

• Forced uncached normal NuGet restore, clean and Release solution build passed with no local project override. Restored TNC and TNC.Gmcp are both 4.9.0 packages. One existing nullable warning in ListEditorTests.cs:191.
• Full suites: Core 1736/1736, Client 245/245, Graphics 99/99, Scripting 92/92, Web 37/37, Tui 3030/3030; Avalonia 924/924, repeated twice. All 6163 tests pass.
• Fixed the aggregate NativePanel timing failure: modal-state notifications are asynchronous, and a fullscreen modal prevents the main pane from repainting. The app now marshals overlay publication to its UI thread; the test awaits the actual PanelsChanged notification while keeping its F4 and empty-panel assertions. No sleeps, skipped tests, or framework changes. An isolated blocked-thread-pool probe reproduced the original ordering; the corrected focused test passed eight independent repetitions.
• New protocol integration cases pass, including fragmented/no-newline queries, control-string shielding and prompt recovery. Focused Avalonia geometry checks pass 8/8, including pointer-absent hosting and handshake/DPI changes.
• Real disposable Linux PTY checks confirm 120x40 cells with 1200x960 pixels reports 10x24; unknown/inexact/redirected cases remain unknown. macOS ABI was reviewed, not executed on macOS.

Status

Draft for review. The earlier unreleased-dependency limitation is resolved by the published TNC 4.9.0 pin; normal package-backed build now passes. No merge, release or deployment performed.

[coderabbitai]

Caution

Review failed

The pull request is closed.

• Autofix · Keep fixing CodeRabbit findings and required CI, and resolving merge conflicts