[feature]: Add timer-based supply commit updates

[ffranr]

Currently issuers must manually call UpdateSupplyCommit RPC endpoint. This is useful for testing and fine-grained control. For example, an issuer may call IgnoreAssetOutPoint multiple times, then call UpdateSupplyCommit once to batch ignores into a single supply commitment. This reduces costs when chain fees are high, since it avoids one transaction per ignore.

Proposal: introduce an optional timer that triggers UpdateSupplyCommit flow periodically, with a no-op if there are no changes. Manual invocation would remain available for explicit batching.

Benefits: simpler UX, better fee efficiency, preserved manual control.

Open questions: decide default interval, add a config option(s).