fix: route configured null-language extensions to line-count instead of skipped-unsupported (#1274)

[alpurkan17]

Summary

Extensions in programming_languages.json with language=null (no tree-sitter parser) receive score=0.0 with scoring_method=skipped-unsupported. The scorer only routed to line-count when the extension appeared in NON_CODE_EXTENSIONS — it never consulted the JSON config for null-language entries.

Affected: env, gitattributes, gitignore, gql, graphql, ipynb, move, nim, pde, puml, tex (11 extensions).

Fix: add an inline check before the skipped-unsupported gate: when the extension is configured in programming_languages with language=None, route to line-count scoring using the configured weight.

No new method, no import changes, no architectural refactor — single inline check in the existing elif chain.

Changes

• tree_sitter_scoring.py: add 11-line elif clause for null-language configs
• test_token_scoring_integration.py: 6 test cases covering positive, negative, weight, regression, and config-coverage

Validation

• ruff check: pass
• ruff format: pass
• pytest: 30/30 pass (24 existing + 6 new)
• graphql → line-count with weight 1.0
• .gitignore → line-count
• unknown.xyz → still skipped-unsupported
• test.py → still tree-diff (no regression)
• All 11 null-language extensions verified via config-coverage test

vs PR #1275

	PR #1275	This PR
Files	3	2
New API	is_line_count_extension() method	None
Import changes	Remove NON_CODE_EXTENSIONS	None
Approach	Add method + refactor gate	Inline elif check
Diff size	+105/−2	+76

Closes #1274