Add repo picker, update checker, and distribution tooling1.0.00.7.00.6.0

Closes #11-#15 (milestones 0.6.0, 0.7.0, 1.0.0).

- Repo picker: on-demand broader OAuth scope (security_events repo),
  requested only when the "Browse your repos" action is used, never by
  default. Lists /user/repos via the existing pagination helper. Granted
  scope persisted with backward-compatible decoding for existing state
  files. Fixed a bug where a failed re-auth force-signed-out a user who
  already had a valid narrower-scope token.
- Update checker: polls this repo's GitHub Releases API, surfaces a
  banner linking to new releases. Skipped on the Mac App Store build via
  a runtime receipt check rather than a separate build configuration.
- Fixed MARKETING_VERSION, stuck at Xcode's default "1.0" this whole
  time unrelated to our git tags — now 1.0.0, matching this release.
- Added PrivacyInfo.xcprivacy (no tracking, no collected data).
- Added scripts/build-dmg.sh (archive, Developer ID export, notarize,
  staple) and Casks/octosentry.rb (Homebrew Cask template), plus
  DISTRIBUTION.md documenting both channels end to end.

Entitlements were already identical across all builds — no divergence
needed there. What remains for actual App Store submission and notarized
DMG builds is account-specific (Apple Developer Program membership,
certificates, App Store Connect submission) and can't be done from here;
documented clearly in DISTRIBUTION.md.

1 files changed, 8 insertions, 0 deletions

diff --git a/octosentry/GitHubAPIModels.swift b/octosentry/GitHubAPIModels.swift
index 3a84aa8..2b95b70 100644
--- a/octosentry/GitHubAPIModels.swift
+++ b/octosentry/GitHubAPIModels.swift
@@ -86,3 +86,11 @@ nonisolated struct SecretScanningAlertDTO: Decodable {
         case validity
     }
 }
+
+nonisolated struct GitHubRepoDTO: Decodable {
+    let fullName: String
+
+    enum CodingKeys: String, CodingKey {
+        case fullName = "full_name"
+    }
+}