fix: add null checks and bounds validation for memory safety

[gavlooth]

Summary

• Add null check after strdup in parse_include to handle allocation failure
• Add bounds check for string parsing to prevent buffer overflow (max 4096 codepoints)
• Add null check after malloc in table_find to handle allocation failure

Test plan

• Existing tests pass
• Manual testing with large strings to verify bounds check

🤖 Generated with Claude Code

[Lorenzobattistela]

This probably has performance implications, doing bound validation is expensive. If possible / want us to review and merge, pls do benchmarking