Add Electron to `clerk init` framework detection and `--framework`

Summary

clerk init cannot set up @clerk/electron. --framework has no electron choice, and detection (packages/cli-core/src/lib/framework.ts FRAMEWORK_MAP) matches an Electron Forge project as React once react is installed (React precedes Vite in the map) or as Vite/JavaScript before that, so init installs @clerk/react or @clerk/clerk-js. clerk env pull writes the right variable name (VITE_CLERK_PUBLISHABLE_KEY) but also writes CLERK_SECRET_KEY, because packages/cli-core/src/commands/env/pull.ts includes the secret key for every npm framework. A secret key has no use in an Electron app, so the docs cannot recommend env pull either.

The Electron docs (clerk/clerk#3382) therefore use the manual Publishable Key step and carry no CLI instructions.

Proposal

Add an entry to FRAMEWORK_MAP before the react and vite entries, since Electron Forge projects contain both:

{
  dep: "electron",
  name: "Electron",
  sdk: "@clerk/electron",
  envVar: "VITE_CLERK_PUBLISHABLE_KEY",
  envFile: ".env",
},

Notes for the implementer:

• @clerk/electron needs electron-store installed alongside it (optional peer used by @clerk/electron/storage); sdkInstall may need to cover both.
• Electron has no secret key; init and env pull should skip CLERK_SECRET_KEY for this framework the way the iOS and Android entries do (extend isNpmFramework/includeSecretKey or add a per-framework flag).
• The Electron renderer's Content Security Policy needs the instance's Frontend API host; the docs put it in .env as VITE_CLERK_FRONTEND_API_HOST, which env pull could write too.
• --starter could scaffold with Electron Forge: npm init electron-app@latest <name> -- --template=vite-typescript plus React, matching the docs quickstart at https://clerk.com/docs/electron/getting-started/quickstart.
• Keyless is not supported by the Electron SDK today (the SDK requires publishableKey).

Follow-up in docs

Once shipped, the quickstart gains a "For AI agents" block with npx clerk@latest init --framework electron and a <PromptOnly> card (tracked in Linear DOCS, linked from the docs PR).

Start with packages/cli-core/src/lib/framework.ts and its FRAMEWORK_MAP, then inspect packages/cli-core/src/commands/env/pull.ts and the init flow. Verify Electron Forge projects are detected as Electron, the Electron SDK and publishable-key environment settings are selected, and CLERK_SECRET_KEY is omitted; check whether starter behavior and existing tests also need updates.