Add CHANGELOG for 1.6.0 release

[philippjfr]

This release adds a number of features including a standalone Modal component, the ability to infer widget parameters from values, and the ability to easily edit a ChatMessage. Additionally it includes a number of enhancements for styling, particularly in dark themes, other enhancements for chat components and a large number of bug fixes. Many thanks for our returning contributor @kdheepak, our new contributors @jonatantreijs and @etihwo, and of course the whole maintainer team including @ahuang11, @MarcSkovMadsen @hoxbro, @maximlt and @philippjfr.

Features

• Add Widget.from_values method (#7033)
• Add a standalone Modal layout (#7083)
• Introduces ChatMessage and ChatFeed edit functionality (#7559)

Enhancements

• Allow ChatFeed.callback_exception to accept a callable and 'traceback' (alias for verbose) (#7558)
• Fix Accordion active_header_background in dark theme (#7576)
• Increase default max character limit on ChatAreaInput (#7562)
• Fix chat message alignment issues (#7563)
• Make Markdown pane line breaking behavior configurable (#7582)
• Improve styling of chat components in dark theme (#7601, #7602)
• Automatically scroll when streaming to ChatFeed and ChatStep (#7608)
• Add support for remote filesystems on FileSelector (#7618)

Bug fixes

• Fix Azure Oauth issues (#7587)
• Correctly display file not found paths in panel convert (#7589)
• Fix Tabulator.patch when table is filtered (#7621)
• Ensure esbuild can be detected on windows during panel compile (#7625)
• Fix various issues styling Tabulator when it is wider than the viewport (#7626)
• Fix resource loading when serving Panel app on nested FastAPI endpoint (#7627)
• Fix panel oauth-secret command (#7628)
• Ensure fonts are applied to NotificationArea (#7633)
• Handle session context where session is not defined (#7634)
• Ensure CompositeWidget can be populated in callback (#7636)
• Correctly identify skimage and PIL packages when converting to pyodide (#7637)
• Ensure we use CDN resources in pyodide (#7638)
• Consistently apply sizing_mode to FileSelector components (#7640)
• Ensure tasks are cancelled correctly (#7641)
• Ensure NotificationArea stylesheet loads in panel-preview (#7643)

Compatibility and Updates

• Update panel convert to latest versions of pyodide and pyscript (#7584)

Documentation

• Ensure Open in JupyterLite links work (#7622)
• Add admonitions for outdated guides and minor corrections (#7635)