build(scripts): add root-level pnpm run storybook script

Adds a storybook script to the root package.json that filters into
the luna-charts package, so Storybook can be launched directly from
the repository root instead of requiring a manual cd into
packages/luna-charts. Updates README.md to document the new command
as part of the standard developer workflow.

Closes #11.

README.md

@@ -86,17 +86,7 @@ pnpm install
 | `pnpm test` | Run the full test suite (unit + component) |
 | `pnpm changeset` | Record a changeset for your change (required for any user-facing change) |
 | `pnpm run docs` | Start the documentation site locally (astroJS) |
-
-### Storybook
-
-Storybook currently needs to be started from within the library package directly:
-
-```bash
-cd packages/luna-charts
-pnpm run storybook
-```
-
-> **Note:** Running Storybook from the repository root isn't set up yet. This is a known gap — contributions to add a root-level `pnpm --filter` script are welcome.
+| `pnpm run storybook` | Start the storybook documentation |
 
 Component and browser tests run inside Docker (`docker-compose.test.yaml`) to guarantee a reproducible browser environment across all contributors and CI — you don't need Playwright browsers installed locally.
 

package.json

@@ -11,6 +11,7 @@
     "changeset": "changeset",
     "version": "changeset version",
     "release": "changeset publish",
+    "storybook": "pnpm --filter luna-charts run storybook",
     "test:unit": "pnpm --filter luna-charts test:unit",
     "test:component": "docker compose -f docker-compose.test.yaml up --build --abort-on-container-exit --exit-code-from test",
     "test": "pnpm test:unit && pnpm test:component"