chore!: rename platform enable/disable to optIn/optOut

[turnipdabeets]

💡 Motivation and Context

Finishes the enable()/disable() → optIn()/optOut() rename from #636/#638 at the platform layer. The public Posthog() API already uses optIn()/optOut(), but PosthogFlutterPlatformInterface (and its IO/web implementations) still exposed enable()/disable(). Both classes are in the public API snapshot, so this is a hard rename for v6 with no deprecation shims.

Breaking for code that calls these methods directly on PosthogFlutterPlatformInterface, PosthogFlutterIO or PosthogFlutterWeb, and for custom implementations and test fakes/mocks that override them; app code calling Posthog().optIn()/optOut() is unaffected.

Method-channel names are unchanged. PosthogFlutterIO still invokes 'enable'/'disable' on the method channel, and PosthogFlutterWeb still dispatches MethodCall('enable'/'disable') to the web handler. Renaming the wire strings would mean touching the Kotlin and Swift handlers and the web handler for no user-visible benefit, so this PR stays Dart-API-only.

Stacked on #637.

💚 How did you test it?

• flutter analyze: no issues
• flutter test: all 781 tests pass
• dart format --set-exit-if-changed: clean
• Regenerated api/posthog_flutter.api.json with scripts/check-api-dart.sh --update

📝 Checklist

• I reviewed the submitted code.
• I added tests to verify the changes.
• I updated the docs if needed.
• No breaking change or entry added to the changelog.

If releasing new changes

• Ran pnpm changeset to generate a changeset file

🤖 Agent context

Autonomy: Human-driven (agent-assisted)

Claude Code renamed the methods, updated the test fake, regenerated the API snapshot, and added a major changeset. The decision to leave the native/web channel method strings alone was made to keep the change Dart-only.

🤖 Generated with Claude Code

[github-actions]

posthog-flutter Compliance Report

Date: 2026-10-07 18:26:48 UTC
Duration: 96545ms

✅ All Tests Passed!

45/45 tests passed

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Capture Tests

✅ 29/29 tests passed

View Details

Test	Status	Duration
Format Validation.Event Has Required Fields	✅	128ms
Format Validation.Event Has Uuid	✅	118ms
Format Validation.Event Has Lib Properties	✅	111ms
Format Validation.Distinct Id Is String	✅	112ms
Format Validation.Token Is Present	✅	113ms
Format Validation.Custom Properties Preserved	✅	112ms
Format Validation.Event Has Timestamp	✅	113ms
Retry Behavior.Retries On 503	✅	5326ms
Retry Behavior.Does Not Retry On 400	✅	2114ms
Retry Behavior.Does Not Retry On 401	✅	2116ms
Retry Behavior.Respects Retry After Header	✅	8115ms
Retry Behavior.Implements Backoff	✅	15441ms
Retry Behavior.Retries On 500	✅	5217ms
Retry Behavior.Retries On 502	✅	5220ms
Retry Behavior.Retries On 504	✅	5223ms
Retry Behavior.Max Retries Respected	✅	15442ms
Deduplication.Generates Unique Uuids	✅	124ms
Deduplication.Preserves Uuid On Retry	✅	5223ms
Deduplication.Preserves Uuid And Timestamp On Retry	✅	10331ms
Deduplication.Preserves Uuid And Timestamp On Batch Retry	✅	5224ms
Deduplication.No Duplicate Events In Batch	✅	117ms
Deduplication.Different Events Have Different Uuids	✅	114ms
Compression.Sends Gzip When Enabled	✅	112ms
Batch Format.Uses Proper Batch Structure	✅	112ms
Batch Format.Flush With No Events Sends Nothing	✅	107ms
Batch Format.Multiple Events Batched Together	✅	119ms
Error Handling.Does Not Retry On 403	✅	2113ms
Error Handling.Does Not Retry On 413	✅	2114ms
Error Handling.Retries On 408	✅	5221ms

Feature_Flags Tests

✅ 16/16 tests passed

View Details

Test	Status	Duration
Request Payload.Request With Person Properties Device Id	✅	11ms
Request Payload.Flags Request Uses V2 Query Param	✅	8ms
Request Payload.Flags Request Hits Flags Path Not Decide	✅	7ms
Request Payload.Flags Request Omits Authorization Header	✅	8ms
Request Payload.Token In Flags Body Matches Init	✅	7ms
Request Payload.Groups Round Trip	✅	9ms
Request Payload.Groups Default To Empty Object	✅	7ms
Request Payload.Person Properties Distinct Id Auto Populated When Caller Omits It	✅	7ms
Request Payload.Disable Geoip False Propagates As Geoip Disable False	✅	6ms
Request Payload.Disable Geoip Omitted Defaults To False	✅	6ms
Request Payload.Flag Keys To Evaluate Contains Only Requested Key	✅	7ms
Request Lifecycle.No Flags Request On Init Alone	✅	2ms
Request Lifecycle.No Flags Request On Normal Capture	✅	108ms
Request Lifecycle.Two Flag Calls Produce Two Remote Requests	✅	12ms
Request Lifecycle.Mock Response Value Is Returned To Caller	✅	7ms
Side Effect Events.Get Feature Flag Captures Feature Flag Called Event	✅	112ms

[dustinbyrne]

The platform rename is consistent across the interface, implementations, and wrapper, with transport and lifecycle behavior preserved. Approving with one non-blocking changeset wording correction below. The Apple dependency failure is also present on the base stack.

AI-assisted review.