types ledger: Pair was blessed in while master was red, and #8418 resolved it #8549

#8535 blessed the type-conflict ledger after the 10-10 burst. That was while #8415 had left a second Pair (#8417), so Pair went in as a known conflict. #8418 renamed the regression spec's type, the conflict is gone, and the types ratchet now fails with "Pair resolved -- remove it from the ledger".

Acceptance criteria

• tri types ratchet prints RATCHET: CLEAN on master.
• docs/reports/type_conflicts.json loses exactly the Pair line.

Boundary

docs/reports/type_conflicts.json

User Scenarios

• Given the type-conflict ledger contains a stale Pair entry from a resolved regression, when running tri types ratchet, then it must print RATCHET: CLEAN and the Pair line must be removed from docs/reports/type_conflicts.json.

Requirements

• FR-001: The Pair conflict entry MUST be removed from docs/reports/type_conflicts.json.
• FR-002: The command tri types ratchet MUST exit 0 and print RATCHET: CLEAN on master.
• FR-003: No other lines in docs/reports/type_conflicts.json MUST be modified.