[Adapter] Consume released Optiflow lossless-PNG replacement profile

[szmyty]

Suite roadmap: #11
Depends on: #73 and egohygiene/optiflow#95
Does not block the first Flow release (#54).

Outcome

Expose Optiflow's independently released, validated lossless-PNG replacement profile through a versioned Flow capability without treating a smaller candidate as permission to mutate a source.

Acceptance criteria

• Lock the exact Optiflow release, OxiPNG provider/validator evidence, profile/schema versions, artifact digests, and supported static PNG subset.
• Present candidate generation, independent validation, transaction approval, quarantine/restore, and irreversible finalization as distinct authority/effect steps in Flow's plan and durable state.
• Preserve source/candidate byte identities, decoded-sample and metadata/chunk preservation evidence, strict size reduction, resource bounds, and no unsupported APNG/interlace claims.
• Reject stale candidates, mismatched locks, larger/invalid outputs, unsupported formats, missing property guarantees, and ambiguous transactions with typed recoverable diagnostics.
• Prove a synthetic clean-install positive route plus failure/interruption/restore fixtures; distinguish encoded-byte savings from observed physical reclamation.
• Publish a compatible Flow release/manifest and docs; preserve independently usable Optiflow and immutable historical Flow releases.

Non-goals

Lossy conversion, bulk media optimization, automatic source replacement, or tests against private user collections.