Fixes #395 
Fixes #270 
Fixes #268

Fixes #393

Fixes #366

This uses Gemini's native [thinking
summaries](https://cloud.google.com/vertex-ai/generative-ai/docs/thinking#thought-summaries)
which were recently added to the API.

Why? The grafted thinking would sometimes cause weird issues where the
model, especially Gemini 2.5 Flash, got confused and put dyad tags like
`<dyad-write>` inside the `<think>` tags.

This also improves the UX because you can see the native thoughts rather
than having the Gemini response load for a while without any feedback.

I tried adding Anthropic extended thinking, however it requires temp to
be set at 1, which isn't ideal for Dyad's use case where we need precise
syntax following.

- [x] add e2e test - happy case (make sure it clears selection and next
prompt is empty, and preview is cleared); de-selection case
- [x] shim - old & new file
- [x] upgrade path
- [x] add docs
- [x] add try-catch to parser script
- [x] make it work for next.js
- [x] extract npm package
- [x] make sure plugin doesn't apply in prod

This code was quite complex and hairy and resulted in very opaque errors
(for both free and pro users). There's not much benefit to budget saver
because Google removed 2.5 Pro free quota a while ago (after it
graduated the model from experimental to preview). Dyad Pro users can
still use 2.5 Flash free quota by disabling Dyad Pro by clicking on the
Dyad Pro button at the top.

#347

Fixes #361

Co-authored-by: graphite-app[bot] <96075541+graphite-app[bot]@users.noreply.github.com>

Co-authored-by: cubic-dev-ai[bot] <191113872+cubic-dev-ai[bot]@users.noreply.github.com>

Fixes #12

Fixes #342

https://github.com/dyad-sh/dyad/issues/244

Fixes #269

Fixes #287