chore(deps): express 4→5 major

[terraboops]

Bumps `@autonav/pack-server` to Express 5.

• `express` `^4.18.2`→`^5.2.1`, `@types/express` `^4.17.21`→`^5.0.6`
• Existing routes already Express-5-safe (named params only; no `*` wildcards, optional params, `app.del`, or regex routes).
• Express 5 breakage fixed: @types/express 5 types `req.params` values as `string | string[]` (path-to-regexp v8). Added param generics to the four route handlers (`Request<{ packName: string }>`, `Request<{ packName: string; version: string }>`) since these routes are always single-value.

Test

• `npm install` (root) — express@5.2.1 resolved for pack-server
• `npm run typecheck` (builds core + comm-layer, typechecks all workspaces) — pass
• `npm test` — pass (autonav 112 passed/9 skipped; comm-layer 45 passed/13 skipped; pack-server has no tests)
• Runtime smoke (built server, Express 5): `GET /health`→200; invalid pack name→400 INVALID_PACK_NAME; unknown route→404 via pathless `app.use`