docs: remove references to the source app and recording

Prepare for open-sourcing: scrub the prior-art attribution from the spec,
agent guide, and code comments so the project documents its own behavior.

- Reword RULES_FEATURE_SPEC.md to describe OpenAppLock's rules feature
  directly (drop the screen-recording source line and "as observed"/
  "not demoed"/"as shown" framing)
- Replace "the reference app/UI/style/defaults" comments and test names
  with direct descriptions of the behavior
- No behavior change; comments, docs, and @Test display names only

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Shared/RuleKind.swift

@@ -5,7 +5,7 @@
 
 import Foundation
 
-/// The three kinds of blocking rules, mirroring the reference app's "New Rule" sheet.
+/// The three kinds of blocking rules offered on the "New Rule" sheet.
 enum RuleKind: String, Codable, CaseIterable, Sendable {
     /// Block selected apps during a recurring time window.
     case schedule
@@ -38,7 +38,7 @@ enum RuleKind: String, Codable, CaseIterable, Sendable {
         }
     }
 
-    /// Default name given to a brand-new rule of this kind (Opal: "In the Zone", "Time Keeper").
+    /// Default name given to a brand-new rule of this kind (e.g. "In the Zone", "Time Keeper").
     var defaultRuleName: String {
         switch self {
         case .schedule: "In the Zone"