Register expanded language grammar coverage

[Mathews-Tom]

Stack: C3 language coverage expansion

Position: 2/4
Base: feat/lang-pack-runtime
Head: feat/lang-expansion-grammars
Next: feat/lang-extraction-fixtures

Changes:

• Register C, C++, PHP, Ruby, Scala, Lua, Bash/Shell, SQL, HTML, CSS, YAML, TOML, JSON, Markdown, and Solidity as chunk-only grammar-backed languages.
• Add central language support metadata and LanguageStats tier reporting.
• Add chunk-only adapters and AST chunk ranges without symbol/import graph claims.

Validation:

• uv run ruff check && uv run ruff format --check . && uv run pyright
• uv run pytest tests/parse/ tests/pipeline/ -q (functional pass; project coverage config makes this subset command exit non-zero)
• uv run pytest -q