feat(memory): bind the memory engine as a loadable TinyBus module - #5512

Reviewed 7 files; 0 findings. The code index for this repository is cold, so this review saw the diff alone.

No findings.

Fixed since the last review

• Pin the Module pass-through policy in redact_outbound
• Round-trip test claims to fill every field but uses Default for the rest — this finding concerns memory_tests.rs, which is not the file under review here and is not included in the diff; cannot verify from memory.rs alone.
• Cover ExportRecord, ImportOutcome and SourceScope serde crossings — same: concerns the test file, not visible in this diff.
• Pin the Module pass-through policy in redact_outbound — concerns a different file (redact_outbound), not shown in this diff.
• Round-trip test claims to fill every field but uses Default for the rest
• Cover ExportRecord, ImportOutcome and SourceScope serde crossings
• Pin the Module pass-through policy in redact_outbound
• Round-trip test claims to fill every field but uses Default for the rest
• Cover ExportRecord, ImportOutcome and SourceScope serde crossings