### What this PR does

Before this PR:
`@uiw/codemirror-extensions-langs`, `@uiw/codemirror-themes-all`, and
`@uiw/react-codemirror` were pinned at version 4.25.1 to work around a
phantom dependency issue.

After this PR:
- All three `@uiw/codemirror-*` packages are upgraded to 4.25.7 with
exact version pinning (no `^` prefix). The phantom dependency issue has
been resolved upstream, making this upgrade safe.
- Added `@codemirror/state` to `pnpm.overrides` to resolve version
duplication, and updated the overrides for `@codemirror/view`,
`@codemirror/language`, and `@codemirror/lint` to their latest versions.

Fixes #12829

### Why we need it and why it was done in this way

The following tradeoffs were made:
- Exact version pinning (removing `^`) is used to prevent unexpected
automatic upgrades that could reintroduce dependency issues.
- `pnpm.overrides` is used to enforce a single version of each
`@codemirror/*` core package across the entire dependency tree. Without
this, multiple versions coexist due to different sub-dependencies
resolving independently, which causes TypeScript errors because
CodeMirror uses private class properties for nominal typing.
- After the update, `@codemirror/state` has multiple dependency versions
(6.5.3 and 6.5.4 coexisting), which declare different types for the same
type name, causing TypeScript errors. Therefore, an override was added
for this dependency.

The following alternatives were considered:
- Using `^4.25.7` (range specifier) was considered but rejected in favor
of exact pinning for more predictable dependency resolution.
- Considered removing the override, but dependency analysis is difficult
to handle because the previous override has already left a fixed version
in the lock file. Deleting the lock file and regenerating it would cause
extensive changes.

Links to places where the discussion took place:
- #12829 — original issue that pinned versions to 4.25.1
- #13133 — also referenced the phantom dependency problem
- uiwjs/react-codemirror#760

### Breaking changes

None.

### Special notes for your reviewer

The `@codemirror/*` override versions are updated as follows:

| Package | Old | New |
|---|---|---|
| `@codemirror/state` | _(none)_ | 6.5.4 |
| `@codemirror/view` | 6.38.1 | 6.39.16 |
| `@codemirror/language` | 6.11.3 | 6.12.2 |
| `@codemirror/lint` | 6.8.5 | 6.9.5 |

### Checklist

- [x] PR: The PR description is expressive enough and will help future
contributors
- [x] Code: [Write code that humans can
understand](https://en.wikiquote.org/wiki/Martin_Fowler#code-for-humans)
and [Keep it simple](https://en.wikipedia.org/wiki/KISS_principle)
- [x] Refactor: You have [left the code cleaner than you found it (Boy
Scout
Rule)](https://learning.oreilly.com/library/view/97-things-every/9780596809515/ch08.html)
- [x] Upgrade: Impact of this change on upgrade flows was considered and
addressed if required
- [ ] Documentation: A [user-guide update](https://docs.cherry-ai.com)
was considered and is present (link) or not required. Check this only
when the PR introduces or changes a user-facing feature or behavior.
- [ ] Self-review: I have reviewed my own code (e.g., via
[`/gh-pr-review`](/.claude/skills/gh-pr-review/SKILL.md), `gh pr diff`,
or GitHub UI) before requesting review from others

### Release note

```release-note
NONE
```

## Problem
Switching between code/preview/split modes in HtmlArtifactsPopup caused
full component unmount/remount due to the switch-based
`renderContent()`, leading to iframe reloads and CodeMirror
re-initialization.

## Solution
- Extract CodePanel and PreviewPanel into `memo` components to prevent
unnecessary re-renders from parent state changes
- Replace switch-based rendering with a controlled `Splitter` that keeps
both panels always mounted, toggling visibility via controlled panel
sizes
- Remember user's custom split position via `splitSizes` state

## Additional Fixes
- Add missing `@codemirror/lang-liquid` peer dependency required by
`@uiw/codemirror-extensions-langs` for HTML syntax highlighting
- Replace hardcoded `white` background with `var(--color-background)`
for proper dark theme support
```release-note
fix: optimize HtmlArtifactsPopup re-rendering
```

### What this PR does

Before this PR:
`@uiw/codemirror-extensions-langs`, `@uiw/codemirror-themes-all`, and
`@uiw/react-codemirror` were pinned at version 4.25.1 to work around a
phantom dependency issue.

After this PR:
- All three `@uiw/codemirror-*` packages are upgraded to 4.25.7 with
exact version pinning (no `^` prefix). The phantom dependency issue has
been resolved upstream, making this upgrade safe.
- Added `@codemirror/state` to `pnpm.overrides` to resolve version
duplication, and updated the overrides for `@codemirror/view`,
`@codemirror/language`, and `@codemirror/lint` to their latest versions.

Fixes #12829

### Why we need it and why it was done in this way

The following tradeoffs were made:
- Exact version pinning (removing `^`) is used to prevent unexpected
automatic upgrades that could reintroduce dependency issues.
- `pnpm.overrides` is used to enforce a single version of each
`@codemirror/*` core package across the entire dependency tree. Without
this, multiple versions coexist due to different sub-dependencies
resolving independently, which causes TypeScript errors because
CodeMirror uses private class properties for nominal typing.
- After the update, `@codemirror/state` has multiple dependency versions
(6.5.3 and 6.5.4 coexisting), which declare different types for the same
type name, causing TypeScript errors. Therefore, an override was added
for this dependency.

The following alternatives were considered:
- Using `^4.25.7` (range specifier) was considered but rejected in favor
of exact pinning for more predictable dependency resolution.
- Considered removing the override, but dependency analysis is difficult
to handle because the previous override has already left a fixed version
in the lock file. Deleting the lock file and regenerating it would cause
extensive changes.

Links to places where the discussion took place:
- #12829 — original issue that pinned versions to 4.25.1
- #13133 — also referenced the phantom dependency problem
- uiwjs/react-codemirror#760

### Breaking changes

None.

### Special notes for your reviewer

The `@codemirror/*` override versions are updated as follows:

| Package | Old | New |
|---|---|---|
| `@codemirror/state` | _(none)_ | 6.5.4 |
| `@codemirror/view` | 6.38.1 | 6.39.16 |
| `@codemirror/language` | 6.11.3 | 6.12.2 |
| `@codemirror/lint` | 6.8.5 | 6.9.5 |

### Checklist

- [x] PR: The PR description is expressive enough and will help future
contributors
- [x] Code: [Write code that humans can
understand](https://en.wikiquote.org/wiki/Martin_Fowler#code-for-humans)
and [Keep it simple](https://en.wikipedia.org/wiki/KISS_principle)
- [x] Refactor: You have [left the code cleaner than you found it (Boy
Scout
Rule)](https://learning.oreilly.com/library/view/97-things-every/9780596809515/ch08.html)
- [x] Upgrade: Impact of this change on upgrade flows was considered and
addressed if required
- [ ] Documentation: A [user-guide update](https://docs.cherry-ai.com)
was considered and is present (link) or not required. Check this only
when the PR introduces or changes a user-facing feature or behavior.
- [ ] Self-review: I have reviewed my own code (e.g., via
[`/gh-pr-review`](/.claude/skills/gh-pr-review/SKILL.md), `gh pr diff`,
or GitHub UI) before requesting review from others

### Release note

```release-note
NONE
```