spec-072 §4 C1/FR-008/AC-5 does not enumerate sub-agent transcripts as a 4th persistence surface

[bug-ops]

Description

specs/072-multimodal-mcp-passthrough/spec.md §4 (invariant C1, FR-008, AC-5) enumerates three persistence surfaces that must strip MessagePart::Image before writes: SQLite parts_json, Qdrant embeddings, and the durable JSONL session log.

#6305 (fixed in #6310) added a fourth strip site: sub-agent transcripts (TranscriptWriter::append in crates/zeph-subagent/src/transcript.rs), which are a structurally separate persistence path that never went through Agent::persist_message. The code now correctly extends the C1 strip principle to this surface, but the spec text itself was not updated to list it.

Flagged during review of #6305/#6310 (both the implementation-critic and code-reviewer independently raised it as a non-blocking spec-currency nit).

Expected Behavior

specs/072-multimodal-mcp-passthrough/spec.md §4 should enumerate sub-agent transcripts as a fourth persistence surface subject to invariant C1, alongside SQLite/Qdrant/durable JSONL, referencing the strip implementation landed in #6310 (MessagePart::strip_images in crates/zeph-llm/src/provider.rs).

Actual Behavior

Spec text only lists three surfaces; the code has since grown a fourth compliant strip site with no corresponding spec update.

Environment

• Version: 0.22.1+ (post-fix(subagent): strip MessagePart::Image from transcript writes #6310)

Related

• zeph-subagent: TranscriptWriter::append has no MessagePart::Image filter (defense-in-depth gap for spec-072 C1) #6305 (fixed by fix(subagent): strip MessagePart::Image from transcript writes #6310)
• Implement: P1 ephemeral persistence strip for MCP image passthrough #6239 (original persistence strip, P1)
• specs/072-multimodal-mcp-passthrough/spec.md §4

Suggested next step

Small doc-only PR updating the spec's enumeration list; no code change required.