[Bug] Inconsistent JournalError wrapping + doubled 'require requires' hint + non-uniform lazy-import

[pathosDev]

Cross-backend inconsistencies surfaced by the audit:

• Error wrapping is uneven — some journal methods wrap driver errors in JournalError, others let raw driver errors escape (matrix differs per backend). Wrap all five Journal methods consistently across backends.
• Doubled verb in the missing-peer-dep hint: context: The Postgres persistence backends require is concatenated by the helper into "...require requires the pg package." (src/persistence/journals/PostgresClient.ts:40, MariaDbClient analogous). Drop the trailing "require".
• Lazy-import is hand-rolled for cassandra-driver/better-sqlite3 instead of the shared lazyImportModule; unify and align install hints.

Part of Phase 1.