## ADDED Requirements

### Requirement: Platform-specific layer graphs are resolved
The system SHALL resolve each bounded Docker tag candidate to the requested platform child manifest and SHALL represent its image contents as the ordered sequence of valid layer digests.

#### Scenario: Multi-platform tag contains the requested platform
- **WHEN** a tag exposes a matching `linux/amd64` child manifest
- **THEN** the system uses that child manifest digest and its ordered layers rather than the top-level index digest

#### Scenario: Candidate manifest is malformed
- **WHEN** a registry response is oversized, malformed, or contains invalid layer identities
- **THEN** the candidate is not represented as a resolved layer graph

### Requirement: Docker selection covers distinct graphs
The system SHALL emit no more than the configured one-to-three image targets per repository and SHALL NOT emit two candidates with identical ordered layer digest sequences.

#### Scenario: Tags alias one graph
- **WHEN** multiple tags resolve to the same ordered layer sequence
- **THEN** only the newest alias remains eligible for selection

#### Scenario: Three or more graphs are available
- **WHEN** at least three distinct graphs resolve successfully
- **THEN** the system selects the newest graph, the remaining graph adding the most not-yet-selected layers, and the oldest remaining distinct graph

#### Scenario: Fewer graphs are available
- **WHEN** fewer distinct graphs resolve successfully than the configured maximum
- **THEN** the system emits only the distinct graphs that exist

#### Scenario: Layer order differs
- **WHEN** two manifests contain the same layer identities in a different order
- **THEN** the system treats them as distinct graphs

### Requirement: Selected Docker targets remain immutable
The system SHALL emit each selected target as the canonical requested-platform manifest digest identity `repository@sha256:<digest>`.

#### Scenario: Selected tag moves later
- **WHEN** a tag is republished after discovery
- **THEN** the queued target continues to identify the originally selected platform manifest digest

### Requirement: Docker graph resolution is bounded and honest
The system SHALL retain hard tag-candidate, selected-graph, response-size, retry, and timeout bounds and SHALL NOT cache partial graph resolution as complete.

#### Scenario: Some manifest requests fail
- **WHEN** at least one candidate graph resolves and another candidate fails transiently
- **THEN** the system may emit the resolved targets for the cycle but records partial resolution and does not write a complete positive cache entry

#### Scenario: Every manifest request fails transiently
- **WHEN** no candidate graph can be resolved because registry metadata is unavailable
- **THEN** the repository remains retryable through the existing deferred-resolution lifecycle