[dbrattli]

Adding BclRune for Rust support in #4997 left six incomplete matches in the JavaScript, Python, and Dart replacement modules. These produce FS0025 warnings during compiler builds and analyzer CI, including on unrelated PRs.

Explicitly reject Rune core-module lookup through the existing FableError path and return None from tryType on those targets, which have no Rune replacement implementation. Keep the matches exhaustive so future builtin additions still produce compiler warnings.

Validation:

• Release build of Fable.Transforms.fsproj with -warnaserror:25: passed, zero warnings or errors.
• Fantomas check on all three changed files: passed.
• git diff --check: passed.

[github-actions]

Python Type Checking Results (Pyright)

Metric	Value
Total errors	34
Files with errors	4
Excluded files	4
New errors	✅ No

Excluded files with errors (4 files)

These files have known type errors and are excluded from CI. Remove from pyrightconfig.ci.json as errors are fixed.

File	Errors	Status
temp/tests/Python/test_hash_set.py	18	Excluded
temp/tests/Python/test_applicative.py	12	Excluded
temp/tests/Python/test_nested_and_recursive_pattern.py	2	Excluded
temp/tests/Python/fable_modules/thoth_json_python/encode.py	2	Excluded

[ncave]

@dbrattli Thanks!