P2-2: Add retry logic to gh API calls

[Cho-Geer]

P2-2: Add retry logic to gh API calls

Parent Epic: #62

Problem

Doc Decompose workflow can fail due to intermittent gh API failures (rate limits, temporary network issues).

Fix

Add exponential backoff retry logic (max 3 attempts) for gh issue create and gh pr create calls.

Files

• .github/workflows/doc-decompose.yml

Verification

Doc Decompose workflow is resilient to transient gh API failures.