Add instance command execution via interactive terminal

[Copilot]

Implements interactive command execution on Incus instances using the /1.0/instances/{name}/exec API endpoint with interactive: true.

Changes

Main Repository

• app/(main)/_lib/instance.ts: Added openExecSocket() method calling exec API, returns WebSocket pair for data/control channels
• app/(main)/instance/console/page.tsx: Added "Execute Command" button, input dialog with quote-aware parser, and interactive terminal display

Submodule (ararat-ui-web)

• components/instance/exec.tsx: New component for command execution terminal
• components/instance/terminalUtils.tsx: Extracted shared terminal logic (themes, socket attachment, resize handling)
• components/instance/textConsole.tsx: Refactored to use shared utilities
• types/instance.d.ts: Extended interface with openExecSocket(command: string[], options?)

Automation

• .github/workflows/sync-submodules.yml: Workflow detects submodule changes, creates PR branches, and opens PRs in submodule repositories

Usage

// Command parsing handles quotes
parseCommand("bash -c 'echo hello world'")  // ["bash", "-c", "echo hello world"]

// Exec socket follows same pattern as console socket
const { data, control } = await instance.openExecSocket(["bash"], { 
  width: terminal.cols, 
  height: terminal.rows 
});

The terminal utilities consolidate Xterm configuration, WebSocket attachment, and resize handling between console and exec components.

Original prompt

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This section details on the original issue you should resolve

<issue_title>Instance Command Execution</issue_title>
<issue_description>Allow for executing custom commands on instances using POST /1.0/instances/{name}/exec

Interactive should always be true. Keep the other keys (other than the command to execute) default.

1. Add a button for command execution on the console page. The InstanceExec should be a component defined via deps/ararat-ui-web (make a PR to that submodule as well), and use similar context to that of the console. Add additional functions to the same class file as needed.
2. When this button is pressed, it should open a dialog. The dialog should ask for the command to execute.
3. Once the command is submitted, the dialog will show an interactive Xterm (similar to how the console works)

If any logic between the existing text console component and this new InstanceExec component are shared, share them. We don't want duplicate logic.</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Instance Command Execution #78

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[github-actions]

🔄 Submodule Sync Status

ℹ️ No submodule changes needed to be synced.

[github-actions]

🔄 Submodule Sync Status

ℹ️ No submodule changes needed to be synced.

[Hye-Dev]

@copilot on the new workflow run: Error: fatal: No url found for submodule path 'app/_components/ui' in .gitmodules
Error: The process '/usr/bin/git' failed with exit code 128

not sure why that path is even being referenced

[Hye-Dev]

We need to have these issues scoped to ararat-ui-web