[fix][committeeptc][node] match anchor BTA by init state

[fengjy73]

Previously, Committee Node could select a stale lane-level TpBTA without considering the BTA subject identity tied to the anchor state. That could cause anchor verification to use the wrong trust anchor after BTA updates. Matching by anchor init state first, then by BTA subject version, keeps the selected TpBTA aligned with the actual BTA used for verification.

• Match anchor BTA by domain, initHeight, and initBlockHash.
• Match TpBTA by CrossChainLane and the matched BTA subject version.
• Reuse the existing TpBTA version when the BTA subject version, PTC anchor version, and endorse root are unchanged.
• Make repeated BTA, TpBTA, and validated consensus state writes idempotent.
• Change system config writes to upsert existing keys.