Implement rec - Phase 4 complete

docs/production-runbook.md

@@ -21,7 +21,9 @@ This runbook is the operational checklist for releasing and monitoring the trans
 
 1. Deploy artifact/config to target environment.
    - V6.0 Phase 1 production stack: `docker compose -f docker-compose.production.yml up -d --build`
+   - `Settings` loads from explicit `_env_file`, then `ENV_FILE`, then the repository-root `.env.production`; it does not resolve relative to the process working directory.
    - For Runtime Settings writes in production, mount `.env.production` into the app container and set `RUNTIME_SETTINGS_ENV_FILE=/app/.env.production`.
+   - If deployment uses a non-default env-file location, set both `ENV_FILE` and `RUNTIME_SETTINGS_ENV_FILE` to that absolute path so startup reads and Settings-page writes stay aligned.
    - For SQLite -> PostgreSQL cutover, run `uv run python tools/export_import_migration.py verify --source-db <sqlite-path-or-url> --target-db <postgres-url>` before switching runtime.
 2. Validate service startup:
    - `/healthz` responds `200`

docs/ui/pages/settings.md

@@ -24,7 +24,8 @@ Settings manages installation-local registries, safe runtime .env settings, and
 - Runtime Settings exposes an allowlisted set of non-secret fields synchronized with `Settings` model fields except excluded secret/unsafe fields.
 - Runtime Settings is rendered as a compact two-column editor (**Setting**, **Value**) in a centered, narrower responsive container.
 - Runtime Settings persists changes to the resolved runtime env file, validates by constructing a `Settings` instance, and reports validation failures through the shared UI error presenter.
-- The write target resolution order is: explicit function override (tests/tools), `RUNTIME_SETTINGS_ENV_FILE` environment variable (deployment override), then `Settings.model_config.env_file` (default `.env.production`).
+- `Settings` resolves its env file in this order: explicit `_env_file`, `ENV_FILE`, then the repository-root `.env.production`.
+- Runtime Settings resolves its write target in this order: explicit function override (tests/tools), `RUNTIME_SETTINGS_ENV_FILE` environment variable (deployment override), `ENV_FILE`, then the repository-root `.env.production`.
 - Runtime Settings changes require application restart to take effect.
 - Runtime Settings renders a host-side restart command (`docker compose -f docker-compose.production.yml up -d --force-recreate app worker`) so operators can apply saved values without granting Docker control to the app container.
 - Runtime Settings includes an explicit "Other settings not shown here" markdown table listing: