ED2KSRV-BUG-001: bound packed-frame decompression

[itlezy]

Summary

• add an independent configurable ceiling for plaintext produced by packed 0xD4 frames
• stop zlib decoding after limit + 1 bytes and return a connection-level frame error
• preserve the existing codec constructor, plain-frame behavior, and outbound compression
• add boundary, high-expansion, truncated-stream, wire-limit, and configuration regressions

Configuration

network.max_decompressed_frame_size defaults to 8_000_000 bytes for existing configurations.

Validation

• python -m emule_workspace build ed2k-server --config Release --build-output-mode ErrorsOnly — passed, Linux x64 release, 0 warnings
• documentation taxonomy, structure, and strict MkDocs validation for the scope split — passed
• workspace product-family validation — reached policy audits, then stopped on 68 pre-existing generated artifacts in unrelated repos (.venv and node_modules); no cleanup was performed
• hosted CI supplies the locked Rust 1.75 tests plus current formatting, Clippy, unit/integration, and release-build gates

Closes #2