refactor: use the shared workflow model from actionslib (#38768)

Pairs with https://gitea.com/gitea/runner/pulls/1143.

Gitea depends on `gitea.com/gitea/runner` for exactly two packages:
`act/model` and `act/exprparser`, the workflow model and the expression
evaluator it needs to parse workflows and to build the task payload the
runner consumes. Pulling the whole runner module in for that is heavy
and puts shared code in the repository of one of the two consumers.

Both packages now live in `gitea.dev/actionslib` (`pkg/model`,
`pkg/exprparser`), the module Gitea and the runner already share for the
runner API, so the dependency on the runner repository is dropped here.

### Changes

- `gitea.com/gitea/runner/act/model` ->
`gitea.dev/actionslib/pkg/model`, `.../act/exprparser` ->
`gitea.dev/actionslib/pkg/exprparser` (22 files, import paths only).
- `routers/api/actions/runner/interceptor.go` takes the `x-runner-uuid`
/ `x-runner-token` names from `gitea.dev/actionslib/pkg/protocol`
instead of repeating the literals the runner also has.
- `go.mod`: `gitea.com/gitea/runner` removed.

---------

Signed-off-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: silverwind <me@silverwind.io>
Co-authored-by: Zettat123 <zettat123@gmail.com>

modules/actions/jobparser/interpeter.go

@@ -4,8 +4,9 @@
 package jobparser
 
 import (
-	"gitea.com/gitea/runner/act/exprparser"
-	"gitea.com/gitea/runner/act/model"
+	"gitea.dev/actionslib/pkg/exprparser"
+	"gitea.dev/actionslib/pkg/model"
+
 	"go.yaml.in/yaml/v4"
 )
 
@@ -59,8 +60,6 @@ func NewInterpeter(
 	ee := &exprparser.EvaluationEnvironment{
 		Github: gitCtx,
 		Env:    nil, // no need
-		// Job must be non-nil because cancelled() dereferences Job.Status unconditionally.
-		// See: https://gitea.com/gitea/runner/src/commit/ad967330a8788c9b8ab723abbc1a86d53c3bc5e6/act/exprparser/functions.go#L299
 		// TODO: The empty JobContext.Status is right for now because Gitea never checks `if` condition when the workflow run is cancelled.
 		// This is an implementation gap in Gitea Actions. When a workflow run is cancelled, Gitea should check the job's `if` condition,
 		// and if the condition is met (e.g. `if: ${{ cancelled() }}` ), the job should be executed rather than cancelled.