## Summary
Adds GitHub and GitLab push webhook support alongside the existing Gitea support.
closes#68
## What Changed
### Auto-detection of webhook source
The webhook handler now auto-detects which platform sent the webhook by examining HTTP headers:
- **Gitea**: `X-Gitea-Event`
- **GitHub**: `X-GitHub-Event`
- **GitLab**: `X-Gitlab-Event`
Existing Gitea webhooks continue to work unchanged. Unknown sources fall back to Gitea format for backward compatibility.
### Normalized push event
All three payload formats are parsed into a unified `PushEvent` struct containing:
- Source platform, ref, branch, commit SHA
- Repository name, clone URL, HTML URL
- Commit URL (with per-platform fallback logic)
- Pusher username/name
### New files
- **`internal/service/webhook/payloads.go`**: Source-specific payload structs (`GiteaPushPayload`, `GitHubPushPayload`, `GitLabPushPayload`), `ParsePushPayload()` dispatcher, per-platform parsers, branch extraction, and commit URL extraction functions.
### Modified files
- **`internal/service/webhook/types.go`**: Added `Source` type (gitea/github/gitlab/unknown), `DetectWebhookSource()`, `DetectEventType()`, and `PushEvent` normalized type. Moved `GiteaPushPayload` to payloads.go.
- **`internal/service/webhook/webhook.go`**: `HandleWebhook` now accepts a `Source` parameter and uses `ParsePushPayload()` for unified parsing instead of directly unmarshaling Gitea payloads.
- **`internal/handlers/webhook.go`**: Calls `DetectWebhookSource()` and `DetectEventType()` to auto-detect the platform before delegating to the webhook service.
- **`internal/service/webhook/webhook_test.go`**: Comprehensive tests for source detection, event type extraction, payload parsing (all 3 platforms), commit URL fallback paths, and integration tests through `HandleWebhook` for GitHub and GitLab sources.
- **`README.md`**: Updated description, features, non-goals, and architecture to reflect multi-platform webhook support.
## Test coverage
Webhook package: **96.9%** statement coverage. Tests cover:
- `DetectWebhookSource` with all header combinations and precedence
- `DetectEventType` for each platform
- `ParsePushPayload` for Gitea, GitHub, GitLab, unknown source, invalid JSON, empty payloads
- Commit URL extraction fallback paths for GitHub and GitLab
- Direct struct deserialization for all three payload types
- Full `HandleWebhook` integration tests with GitHub and GitLab sources
Co-authored-by: user <user@Mac.lan guest wan>
Reviewed-on: sneak/upaas#170
Co-authored-by: clawbot <clawbot@noreply.example.org>
Co-committed-by: clawbot <clawbot@noreply.example.org>
