fix: include documented mix tasks in public API snapshot

[marandaneto]

💡 Motivation and Context

mix posthog.public_api --check is intended to enforce the committed public API snapshot, but it only included modules under PostHog.*. Documented PostHog Mix tasks such as mix posthog.package_source_code are user-facing and appear in HexDocs, but were not covered by the snapshot check.

This updates the snapshot generator to include documented Mix.Tasks.Posthog.* modules. For Mix tasks, the snapshot now records the task name, @shortdoc, and module documentation text so command/options documentation changes are also reviewed through CI.

💚 How did you test it?

• mix format --check-formatted
• mix posthog.public_api --check
• mix compile --warnings-as-errors
• mix test

📝 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 sampo add to generate a changeset file

🤖 Agent context

Autonomy: Human-driven (agent-assisted)

Implemented with Pi in a dedicated git worktree. The chosen approach keeps the existing public_api.snapshot workflow and extends it to documented PostHog Mix tasks instead of introducing a second snapshot file. The Mix task snapshot includes module docs to cover option/usage changes that exported-function metadata cannot capture.

[github-actions]

posthog-elixir Compliance Report

Date: 2026-06-18 15:40:48 UTC
Duration: 107232ms

⚠️ Some Tests Failed

42/45 tests passed, 3 failed

---

Capture Tests

✅ 29/29 tests passed

View Details

Test	Status	Duration
Format Validation.Event Has Required Fields	✅	608ms
Format Validation.Event Has Uuid	✅	608ms
Format Validation.Event Has Lib Properties	✅	608ms
Format Validation.Distinct Id Is String	✅	608ms
Format Validation.Token Is Present	✅	608ms
Format Validation.Custom Properties Preserved	✅	608ms
Format Validation.Event Has Timestamp	✅	608ms
Retry Behavior.Retries On 503	✅	5612ms
Retry Behavior.Does Not Retry On 400	✅	2611ms
Retry Behavior.Does Not Retry On 401	✅	2611ms
Retry Behavior.Respects Retry After Header	✅	5614ms
Retry Behavior.Implements Backoff	✅	15619ms
Retry Behavior.Retries On 500	✅	5612ms
Retry Behavior.Retries On 502	✅	5614ms
Retry Behavior.Retries On 504	✅	5614ms
Retry Behavior.Max Retries Respected	✅	15624ms
Deduplication.Generates Unique Uuids	✅	617ms
Deduplication.Preserves Uuid On Retry	✅	5612ms
Deduplication.Preserves Uuid And Timestamp On Retry	✅	10618ms
Deduplication.Preserves Uuid And Timestamp On Batch Retry	✅	5615ms
Deduplication.No Duplicate Events In Batch	✅	613ms
Deduplication.Different Events Have Different Uuids	✅	611ms
Compression.Sends Gzip When Enabled	✅	608ms
Batch Format.Uses Proper Batch Structure	✅	607ms
Batch Format.Flush With No Events Sends Nothing	✅	606ms
Batch Format.Multiple Events Batched Together	✅	612ms
Error Handling.Does Not Retry On 403	✅	2610ms
Error Handling.Does Not Retry On 413	✅	2610ms
Error Handling.Retries On 408	✅	5614ms

Feature_Flags Tests

⚠️ 13/16 tests passed, 3 failed

View Details

Test	Status	Duration
Request Payload.Request With Person Properties Device Id	✅	7ms
Request Payload.Flags Request Uses V2 Query Param	✅	6ms
Request Payload.Flags Request Hits Flags Path Not Decide	✅	5ms
Request Payload.Flags Request Omits Authorization Header	✅	5ms
Request Payload.Token In Flags Body Matches Init	✅	5ms
Request Payload.Groups Round Trip	✅	5ms
Request Payload.Groups Default To Empty Object	✅	5ms
Request Payload.Person Properties Distinct Id Auto Populated When Caller Omits It	✅	5ms
Request Payload.Disable Geoip False Propagates As Geoip Disable False	✅	5ms
Request Payload.Disable Geoip Omitted Defaults To False	❌	5ms
Request Payload.Flag Keys To Evaluate Contains Only Requested Key	✅	5ms
Request Lifecycle.No Flags Request On Init Alone	✅	2ms
Request Lifecycle.No Flags Request On Normal Capture	✅	607ms
Request Lifecycle.Two Flag Calls Produce Two Remote Requests	✅	9ms
Request Lifecycle.Mock Response Value Is Returned To Caller	❌	5ms
Side Effect Events.Get Feature Flag Captures Feature Flag Called Event	❌	608ms

Failures

request_payload.disable_geoip_omitted_defaults_to_false

Field 'geoip_disable' not found in /flags request body at path 'geoip_disable'. Available keys: ['groups', 'api_key', 'distinct_id', 'flag_keys_to_evaluate', 'group_properties', 'person_properties']

request_lifecycle.mock_response_value_is_returned_to_caller

Last action result missing field 'value'. Keys: ['error', 'success']

side_effect_events.get_feature_flag_captures_feature_flag_called_event

Expected 1 events with name '$feature_flag_called', got 0

[greptile-apps]

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