Add bounded string helpers and safer string handling

[NathanNeurotic]

Summary

• add shared util_safe helper providing bounded copy, snprintf wrapper, and strnlen alternative
• replace unbounded string operations with size-aware variants across main, DVD player handling, PS1 boot parsing, model name, and history code
• include the new utility source in the build outputs

Testing

• Not run (not requested)

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Codex Task

[codacy-production]

Codacy's Analysis Summary

0 new issue (≤ 0 issue)
0 new security issue
20 complexity
0 duplications

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