Update release flow and Sparkle packaging docs

Added instructions for generating Sparkle keypairs and environment variables. Expanded release flow to include notarization and appcast generation steps, and clarified commands for publishing releases and updating the appcast.

Author: Dimillian

AGENTS.md

@@ -21,8 +21,14 @@ Local packaging helpers live in `Scripts/`:
 - `Scripts/package_app.sh`: build and create `CodexSkillManager.app`.
 - `Scripts/sign-and-notarize.sh`: sign + notarize for releases.
 - `Scripts/make_appcast.sh`: generate Sparkle appcast from a zip.
+- `Scripts/generate_sparkle_keys.sh`: generate Sparkle keypair and export private key.
 
-## Release flow (commit → changelog → GitHub release)
+Sparkle env vars (set in `~/.zshrc`):
+- `SPARKLE_PUBLIC_KEY`
+- `SPARKLE_PRIVATE_KEY_FILE`
+- `SPARKLE_FEED_URL`
+
+## Release flow (commit → changelog → notarize → appcast → GitHub release)
 1) Update version: bump `MARKETING_VERSION` in `version.env`.
 2) Build: `swift build`.
 3) Commit + push:
@@ -33,8 +39,13 @@ Local packaging helpers live in `Scripts/`:
 5) Notarize and package:
    - `APP_STORE_CONNECT_API_KEY_P8="/path/to/key.p8" APP_STORE_CONNECT_KEY_ID="..." APP_STORE_CONNECT_ISSUER_ID="..." APP_IDENTITY="Developer ID Application: ..."`
    - `./Scripts/sign-and-notarize.sh`
-6) Publish GitHub release (creates the tag):
-   - `gh release create v<version> CodexSkillManager-<version>.zip --title "Codex Skill Manager <version>" --notes-file /tmp/codexskillmanager-release-notes-<version>.md`
+6) Generate Sparkle appcast entry:
+   - `SPARKLE_PRIVATE_KEY_FILE="..." ./Scripts/make_appcast.sh CodexSkillManager-<version>.zip https://raw.githubusercontent.com/Dimillian/CodexSkillManager/main/appcast.xml`
+   - `git add appcast.xml`
+   - `git commit -m "chore: update sparkle appcast"`
+   - `git push`
+7) Publish GitHub release (creates the tag):
+   - `gh release create v<version> CodexSkillManager-<version>.zip appcast.xml --title "Codex Skill Manager <version>" --notes-file /tmp/codexskillmanager-release-notes-<version>.md`
 
 ## Project layout
 - `Package.swift`: SwiftPM manifest for the executable target.