chore: move dtsx deps to devDependencies and bump to ^0.9.17

dtsx + bun-plugin-dtsx are build-time tools, not runtime dependencies.
0.9.17 brings two scanner / generator fixes that produce correct .d.ts:
  - Line comments inside inline object types no longer chop off the
    rest of the type (was shipping }>): Promise<…> in BrowserPage.d.ts
    in 0.1.2 — broke tsc for every consumer)
  - Type-position imports auto-include the target file so
    VirtualDocumentFragment.d.ts is now actually emitted (was missing
    despite being referenced from VirtualTemplateElement)

Author: chrisbbreuer