Codex: define Image Lab profile contract for Memory Mesh and Lattice query routing

[mdheller]

@codex Please take this workstream.

Context: Lattice QueryRoutingDryRunPlan now carries lab profile refs under a Slash Topics + New Hope + Memory Mesh governance envelope. Image Lab should provide a stable profile contract so query routing and memory policy can select image processing behavior without launching image jobs in dry-run mode.

Scope:

1. Define an image lab profile shape for image metadata extraction, classification, captioning, embedding model selection, retention policy, and evidence refs.
2. Define dry-run profile selection behavior: no image reads, no model execution, no remote calls.
3. Map profile refs to lab://image-lab/default used by Lattice query routing.
4. Add fixture/schema validation.

Acceptance criteria:

• Repo-native contract/spec and fixture exist.
• Dry-run semantics are explicit.
• Contract can be referenced by Memory Mesh and Lattice routing without executing image runtime.