Fix Serial.print((char)value) printing a number instead of a character

[Copilot]

Serial.print((char)value) dispatched to the int overload (or fell through to const char*) because the char and int overloads for Serial.print were disabled, and CIntType.ScoreCastTo didn't differentiate same-name types from cross-type matches.

Changes

• Enable Serial.print char/int overloads — Uncommented print(char) and print(int) in SerialClass header and registered their internal function handlers (SerialPrintC, SerialPrintI)
• Improve CIntType.ScoreCastTo precision — Added score tier 950 for same-name/same-size but different-signedness matches (e.g. signed char → unsigned char), separating them from cross-type matches like char → int (900)

// Before: char→unsigned char and char→int both scored 900
if (Size == it.Size) return 900;

// After: char→unsigned char scores 950, char→int scores 900
if (Name == it.Name && Size == it.Size) return 950;
if (Size == it.Size) return 900;

• Tests — Added SerialPrintCharCast, SerialPrintlnCharCast, GlobalCharVsIntCast, MemberCharVsIntCast verifying correct dispatch when casting int variables to char

int value = 65;
Serial.print((char)value);  // now prints "A", not "65"