fix(q): harden temporal decoding and frame receive

[belowzeroff]

Summary

• reject Q timespan atoms and vectors instead of decoding durations as timestamps
• receive Q frame bodies in 64 KiB chunks to avoid reserving the advertised size before data arrives
• keep the existing 256 MiB frame limit and cover multi-chunk round-trips
• include inet declarations in driver tests for stricter libc/compiler environments

User-facing behavior

• Q timespan values now fail as unsupported instead of appearing as incorrect dates/timestamps
• large Q frames remain supported; an idle peer that advertises a large frame no longer makes the server reserve the full body up front
• no change to ordinary Q connection or frame semantics

Tests

• make recheck
• partial 128 MiB frame memory regression: 4 KiB VmSize growth
• multi-chunk vector round-trip
• codec, exchange, CLI, real-q interop, client, server, and push/poll suites