[sontrinh16]

Summary

Addresses audit finding L-01, where errors from store.Get were silently discarded and reported as missing state.

• Update bond weight, validator coin, lock, and unlock getters to return (value, found, error).
• Propagate store read errors through keeper operations, message handlers, governance handlers, end-block processing, and gRPC queries.
• Return decoding errors for malformed bond weight, lock, and unlock state instead of panicking.
• Correct the module name in the v1-to-v2 migration error message.

Testing

• Add injected store failure coverage for all four getters.
• Add malformed stored-value coverage for bond weights, locks, and unlocks.
• Update existing tests for the new getter signatures.

[hieuvubk]

lgtm