Add PostHog analytics to replace removed Firebase

Wire PostHog iOS SDK into existing EventLogger pattern so all 60+
call sites flow to self-hosted PostHog instance with zero changes.
Sets subscription person properties for segmentation on foreground.

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

Feels.xcodeproj/project.pbxproj

@@ -291,6 +291,7 @@
 			name = "Feels (iOS)";
 			packageProductDependencies = (
 				1C9566432EF8F5F70032E68F /* Algorithms */,
+				1CA00002300000000000002A /* PostHog */,
 			);
 			productName = "Feels (iOS)";
 			productReference = 1CD90AF5278C7DE0001C4FEA /* Feels.app */;
@@ -442,6 +443,7 @@
 			mainGroup = 1CD90AE5278C7DDF001C4FEA;
 			packageReferences = (
 				1C9566402EF8F4D30032E68F /* XCRemoteSwiftPackageReference "swift-algorithms" */,
+				1CA00001300000000000001A /* XCRemoteSwiftPackageReference "posthog-ios" */,
 			);
 			productRefGroup = 1CD90AF6278C7DE0001C4FEA /* Products */;
 			projectDirPath = "";
@@ -1126,6 +1128,14 @@
 				version = 0.2.1;
 			};
 		};
+		1CA00001300000000000001A /* XCRemoteSwiftPackageReference "posthog-ios" */ = {
+			isa = XCRemoteSwiftPackageReference;
+			repositoryURL = "https://github.com/PostHog/posthog-ios";
+			requirement = {
+				kind = upToNextMajorVersion;
+				minimumVersion = 3.0.0;
+			};
+		};
 /* End XCRemoteSwiftPackageReference section */
 
 /* Begin XCSwiftPackageProductDependency section */
@@ -1134,6 +1144,11 @@
 			package = 1C9566402EF8F4D30032E68F /* XCRemoteSwiftPackageReference "swift-algorithms" */;
 			productName = Algorithms;
 		};
+		1CA00002300000000000002A /* PostHog */ = {
+			isa = XCSwiftPackageProductDependency;
+			package = 1CA00001300000000000001A /* XCRemoteSwiftPackageReference "posthog-ios" */;
+			productName = PostHog;
+		};
 /* End XCSwiftPackageProductDependency section */
 	};
 	rootObject = 1CD90AE6278C7DDF001C4FEA /* Project object */;

Feels.xcodeproj/project.xcworkspace/xcshareddata/swiftpm/Package.resolved

@@ -1,6 +1,15 @@
 {
-  "originHash" : "86635982bfc3fdf16c7186cd33e77b4dc10a24ff9127aaee5f4f0a3676ae2966",
+  "originHash" : "c78c8a80b7804fd247bd921ed90ce6861b540454e98acbc02c5827d66a4d2288",
   "pins" : [
+    {
+      "identity" : "posthog-ios",
+      "kind" : "remoteSourceControl",
+      "location" : "https://github.com/PostHog/posthog-ios",
+      "state" : {
+        "revision" : "5afb749442ecf7798a725ccd30342d94abb5e57f",
+        "version" : "3.41.0"
+      }
+    },
     {
       "identity" : "swift-algorithms",
       "kind" : "remoteSourceControl",

Shared/EventLogger.swift

@@ -6,14 +6,17 @@
 //
 
 import Foundation
-// import Firebase  // Firebase removed
+#if canImport(PostHog)
+import PostHog
+#endif
 
 class EventLogger {
     static func log(event: String, withData data: [String: Any]? = nil) {
-        // Firebase Analytics disabled
-        // Analytics.logEvent(event, parameters: data)
         #if DEBUG
         print("[EventLogger] \(event)", data ?? "")
         #endif
+        #if canImport(PostHog)
+        PostHogSDK.shared.capture(event, properties: data)
+        #endif
     }
 }

Shared/FeelsApp.swift

@@ -9,6 +9,7 @@ import SwiftUI
 import SwiftData
 import BackgroundTasks
 import WidgetKit
+import PostHog
 
 @main
 struct FeelsApp: App {
@@ -23,6 +24,13 @@ struct FeelsApp: App {
     @State private var showSubscriptionFromWidget = false
 
     init() {
+        // Initialize PostHog analytics
+        let posthogConfig = PostHogConfig(apiKey: "phc_3GsB3oqNft8Ykg2bJfE9MaJktzLAwr2EPMXQgwEFzAs", host: "https://analytics.88oakapps.com")
+        #if DEBUG
+        posthogConfig.debug = true
+        #endif
+        PostHogSDK.shared.setup(posthogConfig)
+
         BGTaskScheduler.shared.cancelAllTaskRequests()
         BGTaskScheduler.shared.register(forTaskWithIdentifier: BGTask.updateDBMissingID, using: nil) { (task) in
             BGTask.runFillInMissingDatesTask(task: task as! BGProcessingTask)
@@ -115,6 +123,36 @@ struct FeelsApp: App {
                 // Check subscription status (network call) - throttled
                 Task.detached(priority: .background) {
                     await iapManager.checkSubscriptionStatus()
+
+                    // Set PostHog person properties for subscription segmentation
+                    let state = await iapManager.state
+                    let subscriptionStatus: String
+                    let subscriptionType: String
+
+                    switch state {
+                    case .subscribed:
+                        subscriptionStatus = "subscribed"
+                        subscriptionType = await iapManager.currentProduct?.id.contains("yearly") == true ? "yearly" : "monthly"
+                    case .inTrial:
+                        subscriptionStatus = "trial"
+                        subscriptionType = "none"
+                    case .trialExpired:
+                        subscriptionStatus = "trial_expired"
+                        subscriptionType = "none"
+                    case .expired:
+                        subscriptionStatus = "expired"
+                        subscriptionType = "none"
+                    case .unknown:
+                        subscriptionStatus = "unknown"
+                        subscriptionType = "none"
+                    }
+
+                    PostHogSDK.shared.capture("$set", properties: [
+                        "$set": [
+                            "subscription_status": subscriptionStatus,
+                            "subscription_type": subscriptionType
+                        ]
+                    ])
                 }
             }
         }