feat(game): add independent Stardew and Minecraft agents

[shawnmsw28]

Add the Stardew and Minecraft agent implementations under a shared PhyAgentOS/game_agents/ directory, with each game retaining its own execution and memory model.

PhyAgentOS/game_agents/
├── stardew/     # Planner–Actor loop, Core runtime integration and role memory
└── minecraft/  # Skill graph, evidence store and warm-up execution

• Preserve GeneralGameSkillRuntime, register_general_game and paos general-game for Stardew, and AgentFn, WorldAdapter, graph APIs and paos minecraft warmup / benchmark for Minecraft. The two game modules do not import each other.
• Keep the required target, Minecraft bridge and tech-tree harness updates in their existing Core locations. Update imports, packaged resources, tests and English/Chinese documentation for the new directories.
• Include only the agent integration and its supporting changes; Clockwork Demo01, the C# mod, game saves and recorded benchmark outputs are excluded.

This is one commit against feature/general-game-agent at c74eb5366d68a0e69cdd8bbc05776f6754a0fe2f.

Validation: 107 tests passed locally; Ruff, diff checks and the Minecraft bridge JavaScript syntax check passed. A built wheel was installed separately and verified to load both modules, the W01–W07 manifest and all three CLI entry points. The same commit passed Windows and Linux CI in the preparation repository. Game and model boundaries were mocked; live game sessions have not been validated.

Upstream CI passed on Windows and Linux, including tests, CLI entry points and wheel packaging.

Known issues reproduced in a subsequent review, still present in this revision:

• The Minecraft scripted executor checks top-level ok, while MinecraftTargetWorldAdapter returns action failure under info.ok. It can continue to place/craft after an equip failure.
• Graph evidence extraction prefers the planned actions list over executed results. After early termination it can record unexecuted actions as part of a verified failure claim.
• Frozen graph loading validates the exported JSON hash but not the SQLite contents it subsequently reads. Inconsistent JSON/database snapshots can pass the declared hash check.

These cases are not covered by the passing CI suite. This PR retains the current implementation for maintainer review; the above issues remain unresolved.

Replaces #107 with the same commit (6146f41). The PR source now lives in the contributor's fork so the upstream repository does not need a temporary source branch.