fix(updater): set the real Sparkle EdDSA public key (was a placeholder)

[BlackHole1]

What

0.1.0-beta.1 opened with 「无法启动更新程序 / Failed to start updater」 on every launch. Root cause: Sources/CloseUp/Info.plist shipped SUPublicEDKey as the literal REPLACE_WITH_GENERATED_ED25519_PUBLIC_KEY placeholder, so Sparkle could not decode it at startUpdater.

Live Sparkle log from the installed beta.1:

[org.sparkle-project.Sparkle:Sparkle] The provided EdDSA key could not be decoded.
[org.sparkle-project.Sparkle:Sparkle] Fatal updater error (1): The EdDSA public key is not valid for CloseUp.

This sets the real ed25519 public key — the shared signing key whose private half is the SPARKLE_EDDSA_PRIVATE_KEY CI secret; LockIME ships the identical SUPublicEDKey.

Verification

• The key decodes to exactly 32 bytes (the exact check Sparkle does at startUpdater); sign_update --verify of a beta.1 signature against it passes.
• A local Release build embedding it launches with no EdDSA could not be decoded / Fatal updater error in the Sparkle log (vs. beta.1 which logs both).

Out of scope / operational (not in this diff)

Two further one-time release-setup gaps that were also undone (mirrors what LockIME has correct) — handled operationally, not in code:

• CI secret SPARKLE_EDDSA_PRIVATE_KEY value did not sign (both 0.1.0 and beta.1 appcasts shipped without sparkle:edSignature) → re-set from the keychain.
• GitHub Pages was disabled (feed 404'd) → enabled (gh-pages / root); feed now serves 200.

⚠️ 0.1.0-beta.1 and the universal 0.1.0 cannot auto-update to the fix (their embedded key is broken) — those users must download the next build by hand.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: 0e27154e-f9af-47c5-9766-73c514a6a286

📥 Commits

Reviewing files that changed from the base of the PR and between e8a65f4 and b15e36d.

📒 Files selected for processing (2)

• Sources/CloseUp/Info.plist
• Sources/CloseUp/Updates/UpdateController.swift

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Summary by CodeRabbit

• Bug Fixes
  • Updated the app’s update configuration to use a valid signing key, improving updater reliability for release builds.
  • Clarified update behavior so debug builds remain inactive, preventing unintended update checks during development.

Walkthrough

The SUPublicEDKey value in Info.plist is changed from a placeholder string to a real base64-encoded Ed25519 public key, with the adjacent comment updated to describe CI-generated EdDSA signing. The top-of-file documentation comment in UpdateController.swift is reworded to reflect that Release builds require a valid SUPublicEDKey or Sparkle refuses to start, and that Debug builds never start the updater because startingUpdater: false.

🚥 Pre-merge checks | ✅ 4

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title follows the required type(scope): subject format and accurately describes the key update.
Description check	✅ Passed	The description is clearly related to the Sparkle updater key fix and its validation, so it passes.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

✨ Simplify code

• Create PR with simplified code
• Commit simplified code in branch fix/sparkle-eddsa-public-key

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