docs: add contribution baseline and AI use policy, trim agent guides

[dev-jodee]

Summary

• CONTRIBUTING.md: adopt the shared Foundation contribution structure (before-you-start checklist with signed commits, private vulnerability reporting, development setup, change requirements, PR expectations with Greptile resolution and Conventional Commits, license) on top of the existing repo-specific rules, which are unchanged.
• CONTRIBUTING.md: new AI use section covering review responsibility, Solana Dev Skill / Solana MCP pointers, the AI code smells maintainers will close PRs over, disclosure, and reviewer communication. Two rules are specific to a teaching repo: generated code that obscures the pattern being taught is worse than none, and do not fan a change across every framework flavor unless it truly applies.
• AGENTS.md: cut command tables, toolchain-pin lists, and formatting/CI steps that are all readable from package.json, Anchor.toml, and the workflows. Kept only the non-obvious parts: why this is not a pnpm workspace, workspace-ignore enforcement, the litesvm 0.8 override silent-pass trap, node:test-under-mocha exiting 0, resolver-2 feature unification, and the anchor keys sync drift guard. 4.4 KB to 2.3 KB.
• games/gacha/pinocchio/CLAUDE.md and games/world-cup/pinocchio/CLAUDE.md: same treatment. Dropped just command tables, program file trees, account field dumps, and lifecycle walkthroughs; kept the design rationale (gacha's randomness and trust model, world-cup's total ranking key and folded scoring) and the traps (packed-field alignment, Codama literal-array limit, single-threaded light prover, devnet burst cost).

Test Plan

• Docs only, no code paths touched.
• pnpm check (prettier) was not run locally: the root node_modules is not installed in this working copy. CI covers it.

[greptile-apps]

Greptile Summary

This documentation-only PR establishes a broader contribution and AI-use policy while reducing agent guides to repository-specific design decisions and traps.

• Adds contribution setup, security reporting, pull-request, licensing, and AI-assistance expectations.
• Condenses the root agent guide around workspace structure, test-stack hazards, and CI exceptions.
• Condenses the Gacha and World Cup guides around their core mechanics, invariants, and specialized workflows.

Confidence Score: 4/5

The PR appears safe to merge after clarifying the non-blocking test-command guidance for justfile-driven Pinocchio examples.

The documentation changes preserve the checked game and repository invariants, with one misleading framework-wide command that sends contributors in two Pinocchio projects to a nonexistent package script.

Files Needing Attention: CONTRIBUTING.md

Important Files Changed

Filename	Overview
CONTRIBUTING.md	Adds the shared contribution baseline and AI policy, but its blanket Pinocchio test command misses the justfile-driven Gacha and World Cup exceptions.
AGENTS.md	Removes discoverable command details while retaining workspace, test-harness, dependency, and CI traps.
games/gacha/pinocchio/CLAUDE.md	Condenses the guide to the verified VRF trust model, accounting invariants, generation constraints, and specialized testing hazards.
games/world-cup/pinocchio/CLAUDE.md	Condenses the guide to the verified ranking, score-folding, oracle immutability, event, generation, and workspace decisions.

_{Reviews (1): Last reviewed commit: "docs(contributing): add contribution bas..." | Re-trigger Greptile}