refactor: portal-backed app version publishing

[kumailn]

This PR replaces the legacy config-driven dApp publishing CLI surface with the new publishing-portal workflow.

What's changed:

• Removes the old CLI model:
  • Deletes the legacy init, create, validate, and direct publish submit|update|remove|support command paths.
  • Removes the old config, schema-generation, and upload/storage code that supported those flows.
• Introduces the new portal-backed publication flow:
  • Adds the new portal workflow in packages/core/src/portal/*.
  • Routes the CLI through the publishing portal for upload target creation, ingestion polling, release minting, attestation, and store submission.
  • Keeps resume as the supported recovery path for incomplete publications.
• Simplifies the CLI UX and configuration:
  • Lets the portal infer the target app from the APK package name.
  • Improves progress reporting and early error messages.

Verification:

• corepack pnpm --dir packages/cli build
• corepack pnpm --dir packages/cli test -- --runInBand

Manual test samples:

• Local APK sample:
  • DAPP_STORE_API_KEY=... node packages/cli/bin/dapp-store.js --apk-file ./example/files/app-release.apk --whats-new "Bug fixes" --keypair /path/to/signer.json --portal-url https://staging.publish.solanamobile.com
• Hosted APK sample:
  • DAPP_STORE_API_KEY=... node packages/cli/bin/dapp-store.js --apk-url https://example.com/app.apk --whats-new "Bug fixes" --keypair /path/to/signer.json --portal-url https://staging.publish.solanamobile.com