Add solana-subscriptions skill

[Dillxn]

Submission

Adds solana-subscriptions-skill, an agent skill for Solana Native Subscriptions and Allowances.

What it does

• chooses among fixed delegations, recurring delegations, and merchant subscription plans
• converts decimal token amounts to exact integer base units
• maps signers, accounts, instruction lifecycle, cancellation, and rent recovery
• covers collection-worker idempotency and application-level delinquency
• includes version-pinned TypeScript SDK recipes and primary-source references
• includes an offline deterministic planner with eight passing unit tests

Novelty

This targets Solana's native Subscriptions and Allowances primitive released in June 2026, with dedicated coverage of allowances, recurring pulls, merchant plans, and production collection behavior.

Verification

• python3 -m unittest discover -s scripts -p "test_*.py" -v — 8/8 pass
• Codex skill validator — pass
• credential scan — clean
• verified against @solana/subscriptions 0.4.0 and upstream commit d27254afbaa2ae11036e088dc3e9463e8e1d5d3d

License: MIT.