refactor: collapse dead SQLite dual-path code; keep migration-only readers (#2454)
# Remove dead SQLite dual-path code; keep migration-only readers
## Summary
PostgreSQL cutover left hundreds of production dual-path branches
(`backendMode ? PG : SQLite/store.db`) whose SQLite arms only hit
throwing `Database`/`ArchiveDatabase`/`CentralDatabase` stubs. This
change mechanically collapses those unreachable arms so production
authority is AsyncDataLayer/PostgreSQL only, while preserving the six
authorized read-only migration/recovery `DatabaseSync` seams.
## Dual-path mass removed
| Metric | Before | After |
|---|---|---|
| `if (…backendMode)` (non-test) | ~328 | ~70 |
| `store.db` / `this.db` refs in core (non-test) | ~570+ | ~375 (mostly
pure legacy MissionStore/eval/insight SQLite classes + thin getters) |
| Net diff | — | **~6.7k lines removed** across 41 files |
Remaining `backendMode` checks are intentional (incomplete-PG sync
safe-defaults, settings-sync disabled-on-PG, symbol-lock PG-only gates,
“requires PostgreSQL” config versioning throws), not live SQLite
authority.
## Subsystems cleaned
- **Core TaskStore / task-store/***: collapsed if/else and early-return
dual-path across reads, moves, lifecycle, mutations, workflow, archive,
branch/PR, artifacts, comments, audit, project ops, etc. `initImpl` is
PostgreSQL-only (SQLite startup tail deleted).
- **Satellite stores**: automation, agent, routine, plugin, secrets,
approval-request, central-core dual-path arms collapsed.
- **Plugins**: reports async methods, compound-engineering pipeline +
session stores, CLI Printing Press store — SQLite fallbacks removed; PG
required.
- **Engine**: no functional dual-path change beyond whitespace
(settings-sync / peer-exchange PG-disabled behavior kept).
## Six migration-only readers retained (allowlist unchanged)
1. `packages/core/src/postgres/sqlite-migrator.ts`
2. `packages/core/src/project-identity.ts`
3. `packages/core/src/sqlite-validation.ts`
4. `packages/core/src/postgres/startup-factory.ts`
5. `packages/cli/src/commands/db.ts`
6. `scripts/lib/start-local-project.mjs`
Plus low-level `sqlite-adapter` and migrator/startup-import tests.
Inventory ratchet still requires exactly these six `new DatabaseSync(`
production sites, all `readOnly: true`.
## Not treated as SQLite
- `.fusion/project.json`, `task.json`, `agent-log.jsonl` file storage
- AsyncDataLayer / Drizzle PG paths
- Incomplete-PG sync safe-default stubs (still return empty/false/null
under backend without consulting SQLite)
## Verification
- `sqlite-production-reader-inventory.test.ts` — 15/15 pass
- `incomplete-pg-ports.pg.test.ts` — 6/6 pass
- Targeted PG tests (create-task, move, handoff, runtime-persistence,
agent, mission, insight, central-core) — green
- `tsc --noEmit` for `@fusion/core`, `@fusion/engine`,
`@fusion/dashboard` — green
- `scripts/check-no-getdatabase.mjs` — clean
<!-- This is an auto-generated comment: release notes by coderabbit.ai
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## Summary by CodeRabbit
* **Improvements**
* Improved end-to-end consistency by making PostgreSQL/async persistence
the standard across core task/workflow, automation, agents, plugins,
routines, secrets, approvals, central operations, and session storage.
* Unified scheduling, settings, configuration revision writes,
run/workflow selection, queues/leases/transitions, and audit/lifecycle
updates around consistent async transaction behavior.
* **Bug Fixes**
* Fixed edge cases for archived/deleted reads, unarchive/recovery flows,
not-found handling, and task/artifact/document/log/comment operations,
including more reliable emissions and hydration across search/list and
lifecycle operations.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->
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