Add `align` pipeline node

[natashaannn]

Add align pipeline node

Objective

Migrate transcript alignment into the DAG.

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Why this matters

Alignment is one of the most important deterministic transcript stages.

Adding it makes the pipeline meaningfully closer to production.

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Parallelization metadata

Track

pipeline

Depends on

• Add transcribe pipeline node #36

Safe to run in parallel with

• diarize node
• shared typing issues
• remotion utility issues

Merge risk

• medium

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Files in scope

Primary:

• scripts/pipeline/nodes/align.ts

Avoid touching:

• WhisperX implementation details

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Required implementation

1. Implement node wrapper

Expose align as a PipelineNode.

2. Define inputs/outputs

Artifact references only.

3. Delegate to existing alignment behavior

No alignment algorithm changes.

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Constraints

• wrapper only

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Handoff contract

Future stages can depend on aligned transcript artifacts.

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Acceptance criteria

Functional

• align executes through runner

Integration checks

• aligned transcript artifact is created

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Verification commands

Run pipeline through align.

Expected result:

• aligned transcript exists

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Explicitly out of scope

• assign-speakers
• merge-doc

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Suggested branch

refactor/s6-align-node

Suggested commit slug

phase-2-step-2-align-node