feat: add sqlite catalog web app

README.md

@@ -11,6 +11,7 @@ nlc run
 nlc run --from 2026-05-01 --to 2026-05-16
 nlc run --last 30d
 nlc run --enrich-only
+nlc serve
 ```
 
 ## Setup
@@ -22,6 +23,8 @@ nlc run --enrich-only
    - `~/.nlc/gmail-credentials.json`
    - `~/.nlc/sheets-credentials.json`
 5. Run `node dist/index.js run --dry-run` before live writes.
+6. Run `node dist/index.js run` to import into SQLite.
+7. Run `node dist/index.js serve` and open <http://127.0.0.1:3000>.
 
 Tokens are persisted locally under `~/.nlc` and must not be committed.
 
@@ -81,9 +84,23 @@ Start from [config.example.yaml](config.example.yaml). The important choices are
 - `gmail.folder`: the single Gmail label/folder to process.
 - `output.excel.enabled`: writes a local `.xlsx` file.
 - `output.sheets_api.enabled`: enables Google Sheets integration when credentials and spreadsheet ID are configured.
+- `database.enabled`: writes SQLite catalog data during `nlc run`; defaults to `true`.
+- `database.path`: SQLite database path; defaults to `./data/newsletter-catalog.sqlite`.
 - `links.tracking_params`: query parameters stripped during URL normalization.
 - `categories.llm`: optional BYOK categorization provider.
 
+## SQLite and Web App
+
+SQLite is the default catalog store. `nlc run` writes imported links, sponsors, dead links, and run history to the configured database even when spreadsheet outputs are disabled.
+
+Start the local read-only web app with:
+
+```bash
+nlc serve --host 127.0.0.1 --port 3000
+```
+
+The first web UI is intentionally functional: dashboard, links, sponsored links, dead links, and runs.
+
 ## Build and Distribution
 
 The build uses `tsup` for the JavaScript bundle and `@yao-pkg/pkg` for the standalone executable: