feat(actions): support owner-level and global scoped workflows (#38154)

## Summary

This PR adds **scoped workflows** to Gitea Actions. Workflows defined
centrally in a "source" repository that automatically run on every
repository in scope: an organization's repositories, or (for instance
admins) every repository on the instance. Each scoped run executes in
the consuming repository's own context (its runners, secrets, and
branch) while its content is read from the source repository, so an org
or instance can mandate shared CI across many repositories without
copying workflow files into each one.

An owner or instance admin registers source repositories on a settings
page and can mark individual workflows as **required**. A required
scoped workflow cannot be opted out by a consuming repository and gates
its pull-request merges; an optional one can be disabled per repository.
Scoped workflows live under a dedicated `SCOPED_WORKFLOW_DIRS` (default
`.gitea/scoped_workflows`), kept separate from regular `WORKFLOW_DIRS`.

## Main changes

### Configuration 
New `SCOPED_WORKFLOW_DIRS` setting, validated to not overlap with
`WORKFLOW_DIRS`. Default: `.gitea/scoped_workflows`

### Data model & migration
- New `action_scoped_workflow_source` table mapping a registering owner
(`owner_id`, where `0` = instance-level) to a source repository, with a
per-workflow `WorkflowConfigs` map.
- `ActionRun` gains `WorkflowRepoID` / `WorkflowCommitSHA` (the pinned
content source) and an `IsScopedRun` flag.

###  Detection & run creation
On consumer events, scoped workflows from the effective sources (the
owner's own sources plus instance-level ones) are matched and turned
into runs that execute in the consumer's context, with content pinned to
the source repo's default-branch commit.

`on: workflow_run` and `on: schedule` are currently not supported.

###  Opt-out
A consuming repository can disable an optional scoped workflow (tracked
separately from regular `DisabledWorkflows`); required scoped workflows
can never be disabled, opted out, or bypassed.

###  Commit status 
A scoped run's status context format is `"<source repo full name>:
<workflow display name> / <job> (<event>)"`
(for example: `my-org/scoped-workflows: db-tests / test-sqlite
(pull_request)`),
keeping it distinct from a same-named repo-level workflow and from other
sources.

###  Required status checks
Admins mark workflows required and supply status-check patterns.
`EffectiveRequiredContexts` appends those patterns to the branch
protection's required contexts and they are matched
must-present-and-pass. If the status checks from scoped workflows fail,
the PR cannot be merged.

NOTE: scoped workflows' required status checks patterns can protect any
target branch that has a protection rule, even though the rule's "Status
Check" is disabled. A target branch with no protection rule cannot be
protected.

<details>
  <summary>Screenshots</summary>

<img width="1400" alt="image"
src="https://github.com/user-attachments/assets/a5d1db33-15ec-487e-93be-2bc04b4e6643"
/>

</details>


###  Reusable workflows (`uses:`)
A scoped workflow's local `uses: ./...` resolves against the source
repository. `uses:` directory validation honors the
instance-configurable `WORKFLOW_DIRS` and `SCOPED_WORKFLOW_DIRS`
(previously hardcoded to `.gitea`/`.github/workflows`).

###  Manual dispatch
`workflow_dispatch` is supported for scoped workflows (web and API),
resolving inputs/content from the source repo.

###  Performance
A process-local LRU cache keyed by source repo ID for the per-source
workflow parse, so instance-level and owner-level sources don't open the
source repo and parse workflow files on every event.

### UI
Org / user / admin pages to register and remove sources, search
repositories, and mark workflows required with their status-check
patterns. The repository Actions sidebar groups scoped workflows by
source with owner/instance labels and required/disabled badges.

<details>
  <summary>Screenshots</summary>

Scoped workflows setting page:

<img width="1600" alt="image"
src="https://github.com/user-attachments/assets/9d19f667-97a5-4935-92b2-e53f105e3642"
/>


Consumer repo's Actions runs list:

<img width="1600" alt="image"
src="https://github.com/user-attachments/assets/a77241f9-0aa9-41aa-ba73-12a9a688cb64"
/>

- `Owner`: this is a owner-level scoped workflows source repo
- `Global`: this is a global scoped workflows source repo
- `Required`: this scoped workflow is required, repo admin cannot
disable it

</details>

---

Docs: https://gitea.com/gitea/docs/pulls/447

---------

Co-authored-by: bircni <bircni@icloud.com>

options/locale/locale_en-US.json

@@ -3779,6 +3779,7 @@
   "actions.runs.commit": "Commit",
   "actions.runs.run_details": "Run Details",
   "actions.runs.workflow_file": "Workflow file",
+  "actions.runs.workflow_file_no_permission": "No permission to view the workflow file",
   "actions.runs.scheduled": "Scheduled",
   "actions.runs.pushed_by": "pushed by",
   "actions.runs.invalid_workflow_helper": "Workflow config file is invalid. Please check your config file: %s",
@@ -3832,6 +3833,32 @@
   "actions.workflow.enable": "Enable Workflow",
   "actions.workflow.enable_success": "Workflow '%s' enabled successfully.",
   "actions.workflow.disabled": "Workflow is disabled.",
+  "actions.workflow.scope_owner": "Owner",
+  "actions.workflow.scope_global": "Global",
+  "actions.workflow.required": "Required",
+  "actions.workflow.scoped_required_cannot_disable": "This scoped workflow is required and cannot be disabled.",
+  "actions.scoped_workflows": "Scoped Workflows",
+  "actions.scoped_workflows.desc_org": "Register repositories as scoped-workflow sources. Workflow files under the scoped workflow directories of a source repository's default branch run on every repository of this organization, in that repository's own context.",
+  "actions.scoped_workflows.desc_user": "Register repositories as scoped-workflow sources. Workflow files under the scoped workflow directories of a source repository's default branch run on every repository you own, in that repository's own context.",
+  "actions.scoped_workflows.desc_global": "Register repositories as scoped-workflow sources. Workflow files under the scoped workflow directories of a source repository's default branch run on every repository on this instance, in that repository's own context. Because instance-level sources are evaluated on every repository's events, registering them can add overhead on large instances.",
+  "actions.scoped_workflows.add_help": "To provide scoped workflows from a repository, commit the workflow files under <code>%s</code> on its default branch, then register the repository as a source below.",
+  "actions.scoped_workflows.security_note": "A source repository's workflow content is executed in every repository it applies to, and its step scripts and their output are written to that repository's Actions logs and readable by anyone who can view the consuming repository's Actions. Registering a private repository as a source therefore discloses its workflow logic through those logs. Only register repositories whose workflow content may be shared with every consuming repository. If a scoped workflow references a reusable workflow from a private repository, make sure every consuming repository can read it, otherwise the workflow will fail there.",
+  "actions.scoped_workflows.source.add": "Add source repository",
+  "actions.scoped_workflows.source.add_success": "Source repository added.",
+  "actions.scoped_workflows.source.remove_success": "Source repository removed.",
+  "actions.scoped_workflows.source.not_found": "Repository not found.",
+  "actions.scoped_workflows.required.update_success": "Required workflows updated.",
+  "actions.scoped_workflows.required.label": "Mark workflows as required (a required workflow cannot be disabled by repositories):",
+  "actions.scoped_workflows.required.patterns": "Required status check patterns",
+  "actions.scoped_workflows.required.patterns_aria": "Required status check patterns for %s",
+  "actions.scoped_workflows.required.patterns_note": "only enforced while the workflow is required",
+  "actions.scoped_workflows.required.patterns_hint": "Mark the workflow as required to configure its status check patterns.",
+  "actions.scoped_workflows.required.patterns_help": "One status check pattern (glob) per line. A consuming pull request can only be merged once a status matching every pattern has passed. This is enforced on any target branch that has a protection rule, even one with its own status checks disabled; a target branch with no protection rule is not gated.",
+  "actions.scoped_workflows.required.patterns_empty": "Each required workflow needs at least one status check pattern.",
+  "actions.scoped_workflows.required.missing_file": "file no longer in source",
+  "actions.scoped_workflows.required.expected_contexts": "Expected status checks (a check that matches a pattern is marked)",
+  "actions.scoped_workflows.required.no_status_contexts": "This workflow posts no status checks, so marking it required would block every consuming pull request from merging. Uncheck Required.",
+  "actions.scoped_workflows.no_files": "No scoped workflow files were found on the default branch.",
   "actions.workflow.run": "Run Workflow",
   "actions.workflow.create_status_badge": "Create status badge",
   "actions.workflow.status_badge": "Status Badge",