analytics(persistence): file-based store + reconciliation selection (KC-51 ph2)

Phase 2: AnalyticsStore (JSON files under Application Support) with immutable
frozen daily snapshots + immutable, idempotent, deduped weekly/monthly reports,
and 12-month retention pruning. Engine gains completedWeekStartKeys/
completedMonthKeys/missingKeys for idempotent reconciliation selection.

AnalyticsStoreTests: 6 XCTest cases. Verified standalone via swiftc — 23-
assertion temp-dir harness all pass. Registered files via xcodegen.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

KisaniCal.xcodeproj/xcshareddata/xcschemes/KisaniCal.xcscheme

@@ -1,10 +1,11 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <Scheme
-   LastUpgradeVersion = "2660"
-   version = "1.3">
+   LastUpgradeVersion = "1500"
+   version = "1.7">
    <BuildAction
       parallelizeBuildables = "YES"
-      buildImplicitDependencies = "YES">
+      buildImplicitDependencies = "YES"
+      runPostActionsOnFailure = "NO">
       <BuildActionEntries>
          <BuildActionEntry
             buildForTesting = "YES"
@@ -26,7 +27,8 @@
       buildConfiguration = "Debug"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
-      shouldUseLaunchSchemeArgsEnv = "YES">
+      shouldUseLaunchSchemeArgsEnv = "YES"
+      onlyGenerateCoverageForSpecifiedTargets = "NO">
       <MacroExpansion>
          <BuildableReference
             BuildableIdentifier = "primary"
@@ -49,6 +51,8 @@
             </BuildableReference>
          </TestableReference>
       </Testables>
+      <CommandLineArguments>
+      </CommandLineArguments>
    </TestAction>
    <LaunchAction
       buildConfiguration = "Debug"
@@ -70,6 +74,8 @@
             ReferencedContainer = "container:KisaniCal.xcodeproj">
          </BuildableReference>
       </BuildableProductRunnable>
+      <CommandLineArguments>
+      </CommandLineArguments>
    </LaunchAction>
    <ProfileAction
       buildConfiguration = "Release"
@@ -87,6 +93,8 @@
             ReferencedContainer = "container:KisaniCal.xcodeproj">
          </BuildableReference>
       </BuildableProductRunnable>
+      <CommandLineArguments>
+      </CommandLineArguments>
    </ProfileAction>
    <AnalyzeAction
       buildConfiguration = "Debug">