fix(log): mark high totalBalanceChf FinancialDataLog entries of 2026-06-17 as invalid

[TaprootFreak]

Recurrence of the transient accounting spike previously handled for 2026-06-15 (#3889) and 2026-06-16 (#3892). On 2026-06-17, plusBalanceChf jumped ahead of the corresponding minusBalanceChf booking (~07:30–08:05 UTC), inflating totalBalanceChf up to 71'964 CHF before self-correcting back to the normal band once the liability was booked. Deltas at the elevated baseline stayed within financeLogTotalBalanceChangeLimit, so entries were wrongly stamped valid=true.

This follow-up migration marks every FinancialDataLog entry of 2026-06-17 (UTC) with totalBalanceChf > 50 000 as valid=false, so monitoring dashboards and anomaly alerts reflect the period correctly.

• Scope: created in [2026-06-17T00:00:00Z, 2026-06-18T00:00:00Z)
• Threshold: totalBalanceChf > 50000
• Affected rows (verified via /gs/debug): 15 valid=true (07:30:34–08:04:47 UTC); max 71'964 CHF
• COUNT pre-check makes up() a no-op on dev/staging
• down() re-stamps valid=true for the same window/threshold (best-effort, one-shot)

Same shape as #3892 — data-only, no schema change.