chore(deps): declare @earendil-works/pi-ai peer dep and bump dev group

src/index.ts imports @earendil-works/pi-ai directly, but the package was
only available nested under pi-coding-agent's bundled node_modules, so
tsgo failed module resolution since the 06-05 lockfile refresh. Declare
it as a peer dependency so npm hoists it top-level, and apply the
pending dependabot dev-group bumps (@types/node 25.9.2,
@typescript/native-preview 7.0.0-dev.20260610.1, tsx 4.22.4,
vitest 4.1.8).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Author: code-yeongyu