Corpus ratchet red after #8209: constants.t27 discard channel moved (top-level-resync 37 -> 0) #8345

#8209 made specs/math/constants.t27 parse its former forall properties as sampled asserts, so the parser's top-level-resync channel for that spec went from 37 to 0 (total discard 386 -> 349). The suite ratchet treats any moved pin as a failure on purpose (it is an unexpected improvement), so "Corpus ratchet (expected-failure ledger)" is red on every PR since.

Fix: re-record the one entry with t27c suite --ratchet --bless-expectations and keep the ledger's hand-written history notes, which the writer drops.

Acceptance criteria

• t27c suite --corpus-only --ratchet prints RATCHET: CLEAN
• the _why_entries_fell and _why_entries_rose notes are kept

Boundary

docs/reports/suite_expectations.json

User Scenarios

• Given the corpus ratchet ledger at docs/reports/suite_expectations.json contains an outdated entry for specs/math/constants.t27 with a top-level-resync discard count of 37, when the spec was changed by math/constants: compile again and pass 36 of 36, seal v2 (Closes #8301) #8209 so the parser now produces 0 discards for that channel, then running t27c suite --corpus-only --ratchet fails because the ratchet treats the moved pin as an unexpected improvement.
• Given the fix is to re-record the ledger entry for specs/math/constants.t27 using the blessed ratchet command, when the command t27c suite --ratchet --bless-expectations is run, then the ledger updates the discard count from 37 to 0 while preserving the hand-written _why_entries_fell and _why_entries_rose history notes.
• Given the ledger has been re-recorded, when a contributor runs t27c suite --corpus-only --ratchet on any PR, then the command prints RATCHET: CLEAN and exits successfully.

Requirements

• FR-001: The corpus ratchet ledger at docs/reports/suite_expectations.json MUST be updated to reflect the current top-level-resync discard count (0) for specs/math/constants.t27.
• FR-002: The hand-written history notes _why_entries_fell and _why_entries_rose in the ledger MUST be preserved during the re-recording.
• FR-003: The command t27c suite --corpus-only --ratchet MUST print RATCHET: CLEAN and exit 0 after the ledger is updated.
• FR-004: The re-recording MUST be performed using t27c suite --ratchet --bless-expectations as specified in the issue.

Success Criteria

• t27c suite --corpus-only --ratchet prints RATCHET: CLEAN and exits 0
• The ledger file docs/reports/suite_expectations.json shows top-level-resync discard count 0 for specs/math/constants.t27
• The _why_entries_fell and _why_entries_rose notes remain present and unchanged in docs/reports/suite_expectations.json