fix(posthog): disable feature flags, remove plugin_loaded event for billing optimization

- Remove plugin_loaded telemetry from index.ts (was 46.5% of all events, ~2.83M/month)
- Add enableLocalEvaluation: false to prevent feature flag polling/decide calls
- Add strictLocalEvaluation: true to prevent server fallback requests
- Add disableRemoteConfig: true to prevent remote config network requests
- Remove 'plugin_loaded' from PostHogActivityReason type
- Update tests: remove stale mocks, add SDK options verification test
- enableExceptionAutocapture: false already present (kept)

Estimated billing reduction: ~$960+/month from feature flag requests,
plus ~2.83M fewer events/month from plugin_loaded removal.

src/shared/posthog.test.ts

@@ -67,7 +67,7 @@ describe("posthog client creation", () => {
     expect(() => cliPostHog.trackActive("cli", "run_started")).not.toThrow()
     await expect(cliPostHog.shutdown()).resolves.toBeUndefined()
 
-    expect(() => pluginPostHog.trackActive("plugin", "plugin_loaded")).not.toThrow()
+    expect(() => pluginPostHog.trackActive("plugin", "run_started")).not.toThrow()
     await expect(pluginPostHog.shutdown()).resolves.toBeUndefined()
   })
 
@@ -104,9 +104,44 @@ describe("posthog client creation", () => {
     const pluginPostHog = createPluginPostHog()
 
     // then
-    expect(() => pluginPostHog.trackActive("plugin", "plugin_loaded")).not.toThrow()
+    expect(() => pluginPostHog.trackActive("plugin", "run_started")).not.toThrow()
     await expect(pluginPostHog.shutdown()).resolves.toBeUndefined()
   })
+
+  it("passes the strict PostHog constructor options for both clients", async () => {
+    // given
+    enableTelemetryEnv()
+    const capturedOptions: Array<Record<string, unknown>> = []
+
+    mock.module("posthog-node", () => ({
+      PostHog: class {
+        constructor(_apiKey: string, options: Record<string, unknown>) {
+          capturedOptions.push(options)
+        }
+        capture() {}
+        async shutdown() {}
+      },
+    }))
+
+    const { createCliPostHog, createPluginPostHog } = await importPostHogModule()
+
+    // when
+    createCliPostHog()
+    createPluginPostHog()
+
+    // then
+    expect(capturedOptions).toHaveLength(2)
+    for (const options of capturedOptions) {
+      expect(options).toMatchObject({
+        enableExceptionAutocapture: false,
+        enableLocalEvaluation: false,
+        strictLocalEvaluation: true,
+        disableRemoteConfig: true,
+        flushAt: 1,
+        flushInterval: 0,
+      })
+    }
+  })
 })
 
 describe("posthog trackActive emission contract", () => {
@@ -170,7 +205,7 @@ describe("posthog trackActive emission contract", () => {
     const client = posthogModule.createPluginPostHog()
 
     // when
-    client.trackActive("distinct-plugin", "plugin_loaded")
+    client.trackActive("distinct-plugin", "run_started")
 
     // then
     expect(captured).toHaveLength(0)

src/shared/posthog.ts

@@ -29,7 +29,7 @@ const DEFAULT_POSTHOG_API_KEY = "phc_CFJhj5HyvA62QPhvyaUCtaq23aUfznnijg5VaaGkNk7
 
 type PostHogCaptureEvent = Parameters<PostHog["capture"]>[0]
 type PostHogSource = "cli" | "plugin"
-type PostHogActivityReason = "run_started" | "plugin_loaded"
+type PostHogActivityReason = "run_started"
 
 type PostHogClient = {
   trackActive: (distinctId: string, reason: PostHogActivityReason) => void
@@ -151,6 +151,9 @@ export function getPostHogDistinctId(): string {
 export function createCliPostHog(): PostHogClient {
   return createPostHogClient("cli", {
     enableExceptionAutocapture: false,
+    enableLocalEvaluation: false,
+    strictLocalEvaluation: true,
+    disableRemoteConfig: true,
     flushAt: 1,
     flushInterval: 0,
   })
@@ -159,6 +162,9 @@ export function createCliPostHog(): PostHogClient {
 export function createPluginPostHog(): PostHogClient {
   return createPostHogClient("plugin", {
     enableExceptionAutocapture: false,
+    enableLocalEvaluation: false,
+    strictLocalEvaluation: true,
+    disableRemoteConfig: true,
     flushAt: 1,
     flushInterval: 0,
   })