Summary

Restores the behavior deleted in #1843 with freshly written code for #1835. Everything here is new expression; the const tables and header flag constants were rewritten with fresh comments, the _dns record helpers and abstract raisers were reauthored, the outgoing writer paths were reimplemented, and the two example scripts are brand new files. No deletions in this PR, those all live in #1843.

Details

• _write_record now derives the rdata length from the size counter instead of rescanning the data chunks
• the AAAA mnemonic in the type table is now "aaaa"
• fresh docstrings were written for every public member that renders in the API docs, so nothing disappears from Read the Docs
• .pxd locals were updated alongside the new variable names in outgoing.py

Test plan

• full suite against a REQUIRE_CYTHON=1 rebuild, 514 passed
• pure Python spot run with the extensions hidden
• hypothesis fuzz suite for the incoming parser
• verified every docs rendered public member still has a docstring
• blame audit with move and copy detection shows no remaining prose or code expression from the declining contributors, only license headers and published mechanical matches