fix(filter): preserve code around inline block comments

[guyoron1]

Summary

• Fix MinimalFilter silently dropping valid code on lines with inline block comments
• int x = 5; /* comment */ was entirely skipped — code before /* was lost (code loss bug)
• Also affected closing lines of multi-line comments: comment */ int z = 3; dropped int z = 3;
• Restructured block comment handler to extract and keep code before /* and after */, stripping only the comment itself

Before / After

Input	Before	After
int x = 5; /* inline */	line dropped	int x = 5; kept
/* multi\nline */ int z = 3;	int z = 3; dropped	int z = 3; kept
/* full line comment */	line dropped	line dropped (correct)

Test plan

• Added test_inline_block_comment_preserves_code — verifies code before /* is kept
• Added test_multiline_block_comment_closing_preserves_code_after — verifies code after */ is kept
• Added test_full_line_block_comment_still_stripped — verifies full-line comments still removed
• cargo clippy --all-targets passes
• cargo test --all passes

Fixes #2714