bound parameter buffer size before narrowing to SQLINTEGER

[jmestwa-coder]

Summary

Bounds ODBC-reported parameter sizes before converting to SQLINTEGER.

Problem

Parameter sizes are obtained as SQLULEN but later converted to SQLINTEGER.
The previous computation performed arithmetic and narrowing without enforcing
the SQLINTEGER range, which could produce invalid (overflowed) sizes for
out-of-range metadata.

Change

• Compute sizes in size_t
• Bound the character count using:
  max_chars = (INT_MAX - sizeof(CharT)) / sizeof(CharT)
• Derive final byte size from the bounded value
• Cast to SQLINTEGER only after ensuring it is in range
• Apply the same logic consistently for both char and wchar_t paths

Behavior

• Valid inputs: unchanged
• Out-of-range inputs: values are bounded to a safe maximum instead of
  producing invalid sizes

Notes

• Allocation pattern remains unchanged (palloc(paramValueSize + sizeof(CharT)))
• No new control flow or error paths introduced
• Change is localized to size computation only