Fix: Implement RFC 5322 Header Folding for MimeAddressHeader

[srvcti]

This PR fixes a long-standing core bug (// FIXME: need to fold every 75 bytes) in \MimeAddressHeader.java\ where the MIME serialization engine failed to fold extremely long address lists (e.g. \To\ or \Cc\ headers with hundreds of recipients).

Previously, these addresses were concatenated into a single unbroken string. This strictly violated RFC 5322 Section 2.1.1, which mandates that email header lines MUST NOT exceed 998 characters and SHOULD be folded at 78 characters. This bug would cause emails to be hard-rejected (\500 Line too long) by strict upstream MTAs (such as Exchange or spam filters).

This patch natively implements compliant CRLF+Tab whitespace folding at the 76-byte boundary during serialization, ensuring maximum global mail routing compatibility.

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