fix(linux): SQLite drop and rowid guards, ClickHouse keys, lost sessions

[datlechin]

• SQLite Drop Table: refused when another table's foreign key points at it, since foreign_keys makes the drop run an implicit DELETE that fires CASCADE and SET NULL. Checked in the prompt (naming each key) and as a precondition inside the drop's transaction. The drop now runs as a save-ledger entry with a process hold.
• Editor: a session lost with a transaction open is no longer replaced silently. The next run is refused with the rollback message unless the failing run already said so; the run after reopens. "Transaction open" hides once the session is lost.
• ClickHouse saves: a guarded step's probe runs again right before its statement once an earlier statement has landed, so an INSERT then UPDATE of the same key stops the UPDATE (PartiallyApplied).
• SQLite: making a nullable INTEGER column the rowid refuses rows with NULL instead of numbering them; the review dialog says so.
• SQLite: a valid date or time on a dynamic-storage column is kept as typed instead of rewritten.
• ClickHouse: grid rows are keyed and locked by every sorting-key and partition-key column.
• ClickHouse: Time/Time64 read and edit up to ±999:59:59; MySQL keeps its 838-hour bound.
• ClickHouse: comment on why mutations_sync stays 1.
• tablepro-net: TlsSetupError::Rustls comes only from the client certificate step; trust store and protocol failures are the new Setup, so ClickHouse and PostgreSQL report a trust store failure as Other.
• Skipped: ClickHouse DateTime('tz') in the fall-back hour, which needs a product or dependency decision.