Reject stale work across delegation sessions

[bmuddha]

Outcome

Work created during an earlier delegation must not mutate an account after it has been undelegated and delegated again.

The account address stays the same across these sessions, so checking only its address or current delegated flag is insufficient.

Scope

Create a failed, recovery-eligible commit intent during session A and retain its normal persisted record. After that failure, complete a separate undelegation, write a different value on base, and establish session B.

Restart MBV so it examines the old intent. Separately release previously held session-A account/delegation observations after session B is active.

Run both redelegation to the same validator and reassignment to a second private ER. Use different values for old staged state, new base state, and new ER state.

Acceptance criteria

• Recovery of the session-A intent cannot commit or undelegate session B.
• Delayed session-A observations cannot overwrite session-B state.
• After reassignment, the old validator rejects writes and commits while the new validator accepts authorized work.
• Rejecting old work does not prevent fresh session-B commits from completing.