Enable Glint by default for both JS and TS apps

[wagenet]

Summary

Implements RFC #976: Enable Glint by Default for the app blueprint. Glint v2 is now installed and configured for both TS and JS apps.

The blueprint already shipped Glint v2 packages — this PR moves them out of the `<% if (typescript) %>` blocks so JS apps benefit from editor tooling out of the box.

• TS path: `tsconfig.json` and the existing `lint:types: ember-tsc --noEmit` script — unchanged.
• JS path: a new `jsconfig.json` (not `tsconfig.json`) that signals "IDE tooling only, no CLI type-check." Glint deps are installed for editor support; no `lint:types` script is added.
• `@glint/ember-tsc`, `@glint/template`, `@glint/tsserver-plugin`, `@ember/app-tsconfig`, and `typescript` move out of the TS-only conditional in `package.json`.
• The previous `!file.startsWith('types/')` filter for JS apps is dropped — both jsconfig.json and tsconfig.json reference `types/`, and the dir doesn't currently contain blueprint-shipped files.
• `index.js` filters `jsconfig.json` out of TS apps, symmetric to the existing `tsconfig.json` filter for JS apps.

Related

• RFC: Enable Glint by Default emberjs/rfcs#976
• Companion change in upstream ember-cli (legacy app-blueprint inside the monorepo): Switch app and addon blueprints to Glint v2 ember-cli#11015
• Sibling addon-blueprint PR: ember-cli/ember-addon-blueprint (will link)
• Docs: typescript: document Glint as a default ember-learn/guides-source#2211
• Announcement post: Add Glint-by-default announcement post ember-learn/ember-blog#1373

Test plan

• Generate a JS app: `ember new my-app` against this blueprint. Confirm `jsconfig.json` present, no `tsconfig.json`, Glint v2 packages installed.
• Generate a TS app: `ember new my-app --typescript`. Confirm `tsconfig.json` present, no `jsconfig.json`, `lint:types: ember-tsc --noEmit` works.
• CI: existing blueprint tests pass.

Note on archived predecessor

The earlier `embroider-build/app-blueprint` is archived; this PR is the same set of changes adapted for the new structure here.

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