SW-115 — Align Dependabot grouping policy documentation and tests

[dDevAhmed]

Summary

Verify Dependabot cadence/grouping policy matches contributor dependency documentation.

Acceptance Criteria

• npm and Actions schedules/groups are documented accurately;
• major updates remain isolated as intended;
• no auto-merge is introduced;
• repository checks pass.

Dependencies

None.

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🏷 Labels

• Stellar Wave
• type: docs
• area: security
• priority: P2
• difficulty: medium
• points: 150
• workstream: security
• dependencies
• supply-chain