feat: add conversation persistence capability

[roackb2]

Summary

• add a coherent persistence.conversations capability that groups the revisioned session repository with the compaction archive repository
• expose the resolved capability and a lightweight, non-certifying readiness report from the conversation engine
• preserve the Heddle 5.1 separate repository options as deprecated compatibility inputs while detecting incomplete or ambiguous configurations
• carry the capability through the SDK quickstart and update the PostgreSQL + Drizzle recovery reference
• record the progressive-adoption mission and the boundary against a universal storage abstraction in public project guidance

Why

A host can only promise that a completed conversation survives process or replica replacement when sessions and compacted archives follow the same authenticated durability boundary. Configuring the ports independently made it easy to build a session-only integration that looked complete until compaction.

The readiness surface intentionally stays small: it checks Heddle configuration shape and lists the focused evidence a host still owns. It does not attempt to certify a database, auth/RLS, migrations, backup, load, or disaster recovery.

Compatibility

• Existing sessionRepository and archiveRepository inputs continue to work.
• Default file persistence remains zero-configuration.
• A legacy partial configuration remains operational, but readiness reports it as incomplete for completed-conversation durability.
• New capability configuration cannot be mixed with the deprecated options.

Verification

• yarn test:unit — 119 files, 709 tests
• yarn test:integration — 34 files, 310 tests
• yarn typecheck
• yarn lint
• yarn build
• built-root export smoke for ConversationPersistenceService
• PostgreSQL + Drizzle migration and reference verification, including fresh-engine compaction recovery

[chatgpt-codex-connector]

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[chatgpt-codex-connector]

Propagate capability archives to side compaction flows

When a control-plane caller adopts the new persistence.conversations option, the engine's normal turn path uses the paired archive repository, but the manual /compact and direct-shell paths still call ConversationCompactionService.compact with only args.archiveRepository (checked chat-sessions-controller.ts lines 252-260 and 672-677). In that configuration args.archiveRepository is undefined, so compaction falls back to the file archive under stateRoot, leaving remote session records with archive state that was not written to the configured remote archive repository.

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