Add bounded Unity console diagnostics contract

[niqibiao]

Summary

• add the core editor/console.get routing contract
• preflight marker ids as empty or exact 32-character hexadecimal values
• update command counts, bilingual command docs, and changelog
• keep the external interface to one optional argument and two result fields

This PR is stacked on codex/reliability-workflow; it does not modify the command-routing PR.

Validation

• 51/51 local pure-stdlib tests
• offline and live exact-id discovery
• malformed marker rejected locally before Unity dispatch
• Unity 2022 live marker, reload, bounded-output, and missing-marker probes

Companion

Companion unity-csharpconsole package: niqibiao/unity-csharpconsole#7