Release 1.5.1

Bug fixes and code quality improvements:

- Fix mirror index dirtied on every sync (MirrorRecord.updatedAt in equality)
- Fix mirror URL corruption: encode calendar/source IDs before joining with ';'
  and use percentEncodedPath to prevent double-encoding
- Fix cleanup route mutating UI calendar picker selection unnecessarily
- Fix --exit flag redundancy (isCLIRun no longer implies termination)
- Remove dead SKIP_ALL_DAY_DEFAULT constant
- Replace deprecated FileHandle(forWritingAtPath:) with throwing variant
- Add EKEventStoreChanged observer for live calendar list refresh
- Extract AppLogStore into its own file (AppLogStore.swift)
- Add Block.span(start🔚) factory; replace verbose nil-field constructions
- Remove redundant MainActor.run{} wrappers inside @MainActor MirrorEngine
- Fix SettingsPayload indentation inside ContentView

All 45 unit tests pass.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

BusyMirror.xcodeproj/project.pbxproj

@@ -410,7 +410,7 @@
 				"CODE_SIGN_IDENTITY[sdk=macosx*]" = "-";
 				CODE_SIGN_STYLE = Automatic;
 				COMBINE_HIDPI_IMAGES = YES;
-				CURRENT_PROJECT_VERSION = 19;
+				CURRENT_PROJECT_VERSION = 20;
 				ENABLE_PREVIEWS = YES;
 				GENERATE_INFOPLIST_FILE = YES;
 				INFOPLIST_FILE = BusyMirror/Info.plist;
@@ -421,7 +421,7 @@
 					"$(inherited)",
 					"@executable_path/../Frameworks",
 				);
-                MARKETING_VERSION = 1.5.0;
+                MARKETING_VERSION = 1.5.1;
 				PRODUCT_BUNDLE_IDENTIFIER = com.cqrenet.BusyMirror;
 				PRODUCT_NAME = "$(TARGET_NAME)";
 				REGISTER_APP_GROUPS = YES;
@@ -440,7 +440,7 @@
 				"CODE_SIGN_IDENTITY[sdk=macosx*]" = "-";
 				CODE_SIGN_STYLE = Automatic;
 				COMBINE_HIDPI_IMAGES = YES;
-				CURRENT_PROJECT_VERSION = 19;
+				CURRENT_PROJECT_VERSION = 20;
 				ENABLE_PREVIEWS = YES;
 				GENERATE_INFOPLIST_FILE = YES;
 				INFOPLIST_FILE = BusyMirror/Info.plist;
@@ -451,7 +451,7 @@
 					"$(inherited)",
 					"@executable_path/../Frameworks",
 				);
-                MARKETING_VERSION = 1.5.0;
+                MARKETING_VERSION = 1.5.1;
 				PRODUCT_BUNDLE_IDENTIFIER = com.cqrenet.BusyMirror;
 				PRODUCT_NAME = "$(TARGET_NAME)";
 				REGISTER_APP_GROUPS = YES;