feat(actions): add job summaries (GITHUB_STEP_SUMMARY) (#37500)

- Add GitHub-style Actions **job summaries** support
(`GITHUB_STEP_SUMMARY` / `workflow/SUMMARY.md`) and render them on the
run Summary view.
- Store uploaded summaries internally in the DB (not as downloadable
artifacts).
- Add runtime-token endpoint for runners to upload summaries:
- `PUT
/api/actions_pipeline/_apis/pipelines/workflows/{run_id}/jobs/{job_id}/summary`
- Advertise support to runners via `RunnerService.Declare` response
header:
  - `X-Gitea-Actions-Capabilities: job-summary`
- Devtest: extend `/devtest/repo-action-view/...` to include mock
`jobSummaries` for previewing UI rendering.

## Compatibility
- New Gitea + old runner: no summary upload → UI shows nothing (no
behavior change)
- New runner + old Gitea: capability not advertised → runner skips
upload (no behavior change)

## Screenshot:

<img width="2017" height="729"
src="https://github.com/user-attachments/assets/31f8b945-50c4-40e1-9f40-382901a53013"
/>


Fixes #23721
PR on gitea-runner https://gitea.com/gitea/runner/pulls/917

---------

Co-authored-by: silverwind <me@silverwind.io>
Co-authored-by: Claude (Opus 4.7) <noreply@anthropic.com>

models/migrations/migrations.go

@@ -413,6 +413,7 @@ func prepareMigrationTasks() []*migration {
 		newMigration(333, "Add bypass allowlist to branch protection", v1_27.AddBranchProtectionBypassAllowlist),
 		newMigration(334, "Add cancelling support to action runners", v1_27.AddCancellingSupportToActionRunner),
 		newMigration(335, "Add reusable workflow fields and action_run_attempt_job_id_index table for ActionRunJob", v1_27.AddReusableWorkflowFieldsToActionRunJob),
+		newMigration(336, "Add ActionRunJobSummary table", v1_27.AddActionRunJobSummaryTable),
 	}
 	return preparedMigrations
 }

models/migrations/v1_27/v336.go

@@ -0,0 +1,30 @@
+// Copyright 2026 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package v1_27
+
+import (
+	"gitea.dev/models/db"
+	"gitea.dev/modules/timeutil"
+)
+
+func AddActionRunJobSummaryTable(x db.EngineMigration) error {
+	type ActionRunJobSummary struct {
+		ID int64 `xorm:"pk autoincr"`
+
+		RepoID       int64 `xorm:"UNIQUE(summary_key)"`
+		RunID        int64 `xorm:"UNIQUE(summary_key)"`
+		RunAttemptID int64 `xorm:"UNIQUE(summary_key) NOT NULL DEFAULT 0"`
+		JobID        int64 `xorm:"UNIQUE(summary_key)"`
+		StepIndex    int64 `xorm:"UNIQUE(summary_key)"`
+
+		Content     string `xorm:"LONGTEXT"`
+		ContentType string `xorm:"VARCHAR(255) NOT NULL DEFAULT 'text/markdown'"`
+		ContentSize int64  `xorm:"NOT NULL DEFAULT 0"`
+
+		Created timeutil.TimeStamp `xorm:"created"`
+		Updated timeutil.TimeStamp `xorm:"updated"`
+	}
+
+	return x.Sync(new(ActionRunJobSummary))
+}