Generative UI and UI improvements

Generative UI renders HTML artifacts inline in chat, with support for KaTeX math and Chart.js and Plotly charts. This release also adds side-by-side terminal splits, the Darcula theme, and @path/to/file references inside AGENTS.md and custom rule files.

• Added support for referencing and inlining external files directly using @path/to/file syntax within AGENTS.md and custom rule files.
• Added support for rendering YAML frontmatter as a formatted metadata card in markdown files and artifacts.
• Added support for KaTeX math formatting, Chart.js, and Plotly charts in generative UI widgets and artifact previews.
• Added the ability to split terminals side-by-side in the terminal panel using a dedicated split button or keyboard shortcut (Ctrl+Shift+5 on Linux/Windows, Cmd+\ on Mac), complete with draggable divider resizing and tree indicators in the terminal list.
• Added the Darcula theme preset and syntax highlighting color palette.
• Added support for viewing specific page ranges (StartPage and EndPage) in multi-page documents (like PDFs) and specifying image resolution (MediaResolution) in the view_file tool.
• Added support for hover preview card on skills chip in chat.
• Added support for defining a rules: key in custom markdown agent frontmatter to bind specific rule files directly to an agent.
• Added support for discovering custom skills, agents, and rules defined in skills.json, agents.json, and rules.json configuration files located within project subdirectories.
• Several overall UX improvements for performance, accessibility, and project configurations.
• Fixed an issue where slash commands unavailable to a selected custom agent were incorrectly shown in the command menu.
• Fixed an issue where image attachments in the message composer were lost when switching between conversations.
• Fixed an issue where Ogg audio and video files were assigned generic MIME types that could cause model errors.
• Fixed an issue where custom color themes with transparency or alpha channels caused UI text to render in red.
• Fixed an icon mismatch where the title bar overflow menu displayed a generic terminal icon instead of matching the tab icon in the side panel.
• Fixed a memory leak where uncommitted conversation renders could leave agent state updates running in the background.
• Fixed a memory leak where rapidly switching between conversations could leave background streaming connections open indefinitely.
• Fixed an issue where clicking a comment link would not scroll to the comment if it was located below the visible fold in virtualized file and diff viewers.
• Fixed an issue where project folder names with special characters or spaces were improperly decoded twice.
• Fixed an issue where newly added files in the review pane displayed an inaccurate added line count due to trailing newlines.
• Fixed an issue where users authenticated via Workforce Identity Federation (WIF / Enterprise sign-in) were logged out prematurely after one hour due to token refresh endpoint routing.
• Fixed a z-index stacking conflict where inline file change panels overlapped the @-mention dropdown menu.
• Fixed an issue where the side panel overflow menu incorrectly marked the last-clicked action with a checkmark.
• Fixed an issue where form controls and scrollbars inside generative UI widgets did not adapt to the dark or light theme.
• Fixed an issue where Enterprise users authenticating via Application Default Credentials could erroneously see an "Out of credits" error message.
• Fixed cold-start token endpoint routing to prevent HTTP 429 resource exhaustion errors on launch, and cached account authentication status to eliminate redundant backend checks on user interactions.
• Fixed an issue where long terminal commands in permission prompts caused the popup layout to overflow.
• Fixed an issue where rapid consecutive agent status updates caused repeated notification chime sounds.
• Fixed an issue where expanded tool steps and collapsible sections could collapse or remount when earlier steps updated during long conversations.
• Fixed an issue where disabled menu items displayed an active pointer cursor instead of a disabled cursor.
• Fixed an issue where previously configured command permission allow and deny rules were ignored after migrating to the updated permissions system.
• Disabled the Git Push action in repositories without a configured remote, and added clear tooltips explaining why VCS actions are disabled.
• Fixed an issue where pasting text into the integrated terminal using Ctrl+V failed unless clipboard read permissions were explicitly granted.
• Fixed an issue where artifacts created in nested subdirectories could fail to appear in the artifacts panel.
• Fixed an issue where signed-in users clicking "Manage" in Settings briefly saw an unauthenticated account overlay.
• Fixed an issue where selecting text in an assistant response failed to show the "Quote" button if the mouse drag released below the message bubble.
• Fixed authentication race conditions that could cause error loops when signing in again or leave stale account state after signing out.
• Fixed an issue where a single corrupted or empty project file could cause the entire projects sidebar to appear empty.
• Fixed an issue in the file viewer where selecting a single code token or word failed to display the comment button.
• Fixed an issue where temporary network disruptions or DNS lookup timeouts during startup caused permanent account failure screens instead of automatically retrying.