fix(terminal): terminal fails to open with custom node

[Jem256]

Closes #1359

Description

When using a custom-built LND image in a Polar network, the terminal window opens for a fraction of a second and immediately closes. The cause is two hardcoded assumptions in DockerTerminal.tsx: the exec requires /bin/bash and a user named lnd to exist in the container. Polar's managed images satisfy both via their entrypoint scripts, but custom images don't. So the exec fails silently, and the window closes before anyone can see why.

This PR tries the expected user and shell first, then falls back to the image's default user and to /bin/sh if needed, printing a note in the terminal whenever it falls back. If every attempt fails, the window now stays open and shows the error instead of closing.

Steps to Test

1. Build a custom LND Docker image
2. Add the custom image to Polar via Managed Images > Add a Custom Node.
3. Create a new network and add the custom LND node.
4. Start the network.
5. Click on the node and click the Terminal tab.

The terminal window should stay open, show a note that it's connected as the image's default user, and give you a working shell.

Screenshots

[greptile-apps]

Greptile Summary

Fixes terminal startup for custom node images by trying alternate users and shells.

• Tries the configured user with bash and sh before retrying with the image's default user.
• Inspects each exec attempt and reports accumulated startup errors in the terminal.
• Keeps failed terminal sessions visible and adds localized fallback diagnostics.

Confidence Score: 3/5

The PR should not merge until CLI aliases remain usable when the terminal falls back to an image's default user.

The new fallback successfully opens a shell under a different home directory, but existing aliases still resolve node configuration and credentials through that user's home, leaving common node CLI commands broken on the path this change is intended to repair.

src/components/terminal/DockerTerminal.tsx

Important Files Changed

Filename	Overview
src/components/terminal/DockerTerminal.tsx	Adds user and shell fallback attempts with persistent diagnostics, but default-user sessions can make home-relative CLI aliases target the wrong configuration directory.
src/i18n/locales/en-US.json	Adds localized messages for user fallback, shell fallback, and complete exec failure.

Flowchart

%%{init: {'theme': 'neutral'}}%%
flowchart TD
    A[Open node terminal] --> B[Configured user + bash]
    B -->|fails| C[Configured user + sh]
    C -->|fails| D[Image default user + bash]
    D -->|fails| E[Image default user + sh]
    B -->|runs| F[Connect stream]
    C -->|runs| F
    D -->|runs| F
    E -->|runs| F
    E -->|fails| G[Display accumulated errors]
    F --> H[Install CLI aliases]
    H --> I[Interactive terminal]

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_{Reviews (1): Last reviewed commit: "fix(terminal): fall back when a custom i..." | Re-trigger Greptile}

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (ef4324b) to head (0b3fa21).

Additional details and impacted files

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  Coverage   100.00%   100.00%           
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  Files          211       211           
  Lines         7190      7190           
  Branches      1447      1447           
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  Hits          7190      7190           

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[Abdulkbk]

Reviewed and left a few feedback