fix(ci): repair YAML syntax in sync-alpha-from-main workflow

[Gkrumbach07]

Summary

• Fixes broken sync-alpha-from-main.yml workflow (failed run)
• Root cause: heredocs (cat <<'MSG') inside YAML run: | blocks produce content at column 0, which YAML parsers interpret as new mapping keys
• Replaced heredocs with shell string assignments and built the PR body incrementally to keep all content properly indented

Test plan

• YAML lint passes locally (yaml-lint)
• Workflow runs successfully on next push to main or via workflow_dispatch

🤖 Generated with Claude Code

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No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: ASSERTIVE

Plan: Pro

Run ID: 37b02bf8-fe20-402b-a6d1-f2d0780891fe

📥 Commits

Reviewing files that changed from the base of the PR and between 374ed47 and 80652eb.

📒 Files selected for processing (1)

• .github/workflows/sync-alpha-from-main.yml

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Walkthrough

The workflow's fallback merge path is refactored to replace heredoc-based string construction with direct variable assignment and dynamic string concatenation for building PR messages and bodies. No control-flow changes occur.

Changes

Cohort / File(s)	Summary
GitHub Actions Workflow Refactoring .github/workflows/sync-alpha-from-main.yml	Replaces heredoc syntax for MERGE_MSG and CONFLICT_MSG with single-quoted incremental string assembly. Refactors PR creation to build PR_BODY via printf/concatenation and passes --body "${PR_BODY}" instead of an inline heredoc argument.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~12 minutes

🚥 Pre-merge checks | ✅ 3

✅ Passed checks (3 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title directly describes the main change: fixing YAML syntax issues in the sync-alpha-from-main workflow, which is the primary objective of the PR.
Description check	✅ Passed	The description clearly explains the problem (heredocs breaking YAML parsing), the solution (replacing with string assignments), and provides test verification details, all directly related to the changeset.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/sync-alpha-yaml-syntax

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