fix(card-browser): render code blocks in error messages

[DebugWithAryan]

Purpose / Description

When a card-browser search produces an error wrapped in <pre>...</pre>
by the Anki backend (e.g. re:b[ triggers a regex parse error), the
error dialog displayed the literal <pre> and </pre> tags instead
of rendering the code block. Anki Desktop renders these via Qt's HTML
support; AnkiDroid uses a plain TextView, so the markup leaked
through.

Fixes

• Fixes Render code blocks in error messages #21001

Approach

• Add formatErrorMessage(message, codeBackgroundColor) in
  com.ichi2.utils that strips <pre> tags and applies
  TypefaceSpan("monospace") + BackgroundColorSpan to the inner
  content.
• Add a Context.formatErrorMessage(message) extension that resolves
  the code-block background from ?attr/colorSurfaceContainerHighest
  via the existing Themes.getColorFromAttr helper, so it adapts to
  light/dark themes.
• Call it from Context.showError so every error dialog benefits.
• Whitespace inside the <pre> block is preserved so caret indicators
  (e.g. ^ under the offending character of a regex) stay aligned.

How Has This Been Tested?

• New unit tests in ErrorMessageFormatterTest:
  • plain message passes through unchanged
  • <pre>regex parse error: …</pre> becomes plain text with a
    TypefaceSpan("monospace") over the code range
• Manually verified by searching re:b[ and and in the card browser
  on a debug build.

Checklist

• You have a descriptive commit message with a short title (first line, max 50 chars).
• You have commented your code, particularly in hard-to-understand areas
• You have performed a self-review of your own code
• UI changes: include screenshots of all affected screens (in particular showing any new or changed strings)
• UI Changes: You have tested your change using the Google Accessibility Scanner

[welcome]

First PR! 🚀 We sincerely appreciate that you have taken the time to propose a change to AnkiDroid! Please have patience with us as we are all volunteers - we will get to this as soon as possible.

[ZornHadNoChoice]

The grey bar is an Emulator bug according to David, but what about the background color of the "code" text? I'm not a fan.

[DebugWithAryan]

Yes, I have removed that text highlighted background @ZornHadNoChoice

[DebugWithAryan]

@ZornHadNoChoice guide me if any changes required

[ZornHadNoChoice]

Visually, it looks fine (aside from the emulator bug). You have to wait for the devs to comment on the code.

[DebugWithAryan]

Visually, it looks fine (aside from the emulator bug). You have to wait for the devs to comment on the code.

Ok thank you

[criticalAY]

Can you confirm you didn't use an LLM to write this? (I can see LLM usage in description)

We want new contributors to gain hands-on experience with our code. While LLMs are efficient, using them for beginner-level issues takes away the chance for developers to learn by doing.

https://github.com/ankidroid/Anki-Android/blob/main/AI_POLICY.md#new-contributors

[DebugWithAryan]

Can you confirm you didn't use an LLM to write this? (I can see LLM usable in description)

We want new contributors to gain hands-on experience with our code. While LLMs are efficient, using them for beginner-level issues takes away the chance for developers to learn by doing.

https://github.com/ankidroid/Anki-Android/blob/main/AI_POLICY.md#new-contributors

No I haven't used LLM for description I just checked other PR's for description idea as I'm new to this.

[david-allison]

We should match Anki Desktop here and let them fix the output.

Only handle backticks for now, as that's known to be handled upstream

https://forums.ankiweb.net/t/bug-regex-parse-error-dialog/69660