Add shared pipeline type contracts

[natashaannn]

Add shared pipeline type contracts

Objective

Define shared pipeline artifact and node contracts in a dedicated type module.

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Why this matters

As pipeline nodes increase, contracts should stop living inside implementation files.

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Parallelization metadata

Track

scripts

Depends on

• Introduce pipeline node contract #24 can already exist, but this issue formalizes shared contracts

Safe to run in parallel with

• pipeline node issues
• remotion utility issues

Merge risk

• low

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Files in scope

Primary:

• scripts/types/pipeline.ts

May touch:

• scripts/pipeline/dag.ts

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Required implementation

1. Define shared types

At minimum:

• ArtifactRef
• PipelineNode
• PipelineRunResult

2. Re-export or migrate current DAG types

Avoid duplicate contract definitions.

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Constraints

• type-only work

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Handoff contract

All future pipeline files should import from scripts/types/pipeline.ts.

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Acceptance criteria

Functional

• no duplicate pipeline type definitions remain

Integration checks

• DAG compiles against shared types

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Verification commands

tsc --noEmit

Expected result:

• zero errors

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Explicitly out of scope

• runner behavior changes

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Suggested branch

refactor/s6-pipeline-types

Suggested commit slug

phase-3-step-5-pipeline-types