Add JetBrains Gateway EAP cask

[Copilot]

Adds a Homebrew Cask for JetBrains Gateway EAP, which was previously missing from the tap.

Changes

• Casks/jetbrains-gateway-eap.rb — New cask modeled after the stable jetbrains-gateway cask with EAP-specific adjustments:
  • Livecheck targets type=eap from the JetBrains data services API (code=GW)
  • rename stanza handles inconsistent .app naming across EAP builds
  • Binary symlinked as jetbrains-gateway-eap to coexist with the stable gateway
  • URL follows the stable Gateway pattern (version.csv.first) rather than the build-number pattern used by most other IDE EAP casks in this tap
• README.md — Added jetbrains-gateway-eap to the cask list (alphabetical order)

Note: sha256 values are placeholders — the hourly bump workflow will populate them with correct values on first run.

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[Goooler]

@copilot Rename the cask to jetbrains-gateway-eap, and review the changes ref https://github.com/Homebrew/homebrew-cask/blob/HEAD/Casks/j/jetbrains-gateway.rb

[Copilot]

@copilot Rename the cask to jetbrains-gateway-eap, and review the changes ref https://github.com/Homebrew/homebrew-cask/blob/HEAD/Casks/j/jetbrains-gateway.rb

Done in 3780b59. Renamed the cask file and all internal references from gateway-eap to jetbrains-gateway-eap, and updated the README list accordingly (alphabetically between intellij-idea-eap and phpstorm-eap).