Merge gitea/act into act/

Merges the `gitea.com/gitea/act` fork into this repository as the `act/`
directory and consumes it as a local package. The `replace github.com/nektos/act
=> gitea.com/gitea/act` directive is removed; act's dependencies are merged
into the root `go.mod`.

- Imports rewritten: `github.com/nektos/act/pkg/...` → `gitea.com/gitea/act_runner/act/...`
  (flattened — `pkg/` boundary dropped to match the layout forgejo-runner adopted).
- Dropped act's CLI (`cmd/`, `main.go`) and all upstream project files; kept
  the library tree + `LICENSE`.
- Added `// Copyright <year> The Gitea Authors ...` / `// Copyright <year> nektos`
  headers to 104 `.go` files.
- Pre-existing act lint violations annotated inline with
  `//nolint:<linter> // pre-existing issue from nektos/act`.
  `.golangci.yml` is unchanged vs `main`.
- Makefile test target: `-race -short` (matches forgejo-runner).
- Pre-existing integration test failures fixed: race in parallel executor
  (atomic counters); TestSetupEnv / command_test / expression_test /
  run_context_test updated to match gitea fork runtime; TestJobExecutor and
  TestActionCache gated on `testing.Short()`.

Full `gitea/act` commit history is reachable via the second parent.

Co-Authored-By: Claude (Opus 4.7) <noreply@anthropic.com>

act/runner/testdata/uses-nested-composite/composite_action2/action.yml

@@ -0,0 +1,63 @@
+---
+name: "Test Composite Action"
+description: "Test action uses composite"
+
+inputs:
+  test_input_optional:
+    description: Test
+
+runs:
+  using: "composite"
+  steps:
+  - uses: actions/setup-node@v3
+    with:
+      node-version: '16'
+  - run: |
+      console.log(process.version);
+      console.log("Hi from node");
+      console.log("${{ inputs.test_input_optional }}");
+      if("${{ inputs.test_input_optional }}" !== "Test") {
+        console.log("Invalid input test_input_optional expected \"Test\" as value");
+        process.exit(1);
+      }
+      if(!process.version.startsWith('v16')) {
+        console.log("Expected node v16, but got " + process.version);
+        process.exit(1);
+      }
+    shell: node {0}
+  - uses: ./uses-composite/composite_action
+    id: composite
+    with:
+      test_input_required: 'test_input_required_value'
+      test_input_optional: 'test_input_optional_value'
+      test_input_optional_with_default_overriden: 'test_input_optional_with_default_overriden'
+      test_input_required_with_default: 'test_input_optional_value'
+      test_input_required_with_default_overriden: 'test_input_required_with_default_overriden'
+      secret_input: ${{inputs.test_input_optional}}
+    env:
+      secret_input: ${{inputs.test_input_optional}}
+  - run: |
+      echo "steps.composite.outputs.test_output=${{ steps.composite.outputs.test_output }}"
+      [[ "${{steps.composite.outputs.test_output == 'test_output_value'}}" = "true" ]] || exit 1
+    shell: bash
+  - run: |
+      echo "steps.composite.outputs.secret_output=${{ steps.composite.outputs.secret_output }}"
+      [[ "${{steps.composite.outputs.secret_output == format('{0}/{0}', inputs.test_input_optional)}}" = "true" ]] || exit 1
+    shell: bash
+  # Now test again with default values
+  - name: ./uses-composite/composite_action with defaults
+    uses: ./uses-composite/composite_action
+    id: composite2
+    with:
+      test_input_required: 'test_input_required_value'
+      test_input_optional_with_default_overriden: 'test_input_optional_with_default_overriden'
+      test_input_required_with_default_overriden: 'test_input_required_with_default_overriden'
+
+  - run: |
+      echo "steps.composite2.outputs.test_output=${{ steps.composite2.outputs.test_output }}"
+      [[ "${{steps.composite2.outputs.test_output == 'test_output_value'}}" = "true" ]] || exit 1
+    shell: bash
+  - run: |
+      echo "steps.composite.outputs.secret_output=$COMPOSITE_ACTION_ENV_OUTPUT"
+      [[ "${{env.COMPOSITE_ACTION_ENV_OUTPUT == 'my test value' }}" = "true" ]] || exit 1
+    shell: bash

act/runner/testdata/uses-nested-composite/push.yml

@@ -0,0 +1,15 @@
+name: uses-docker-url
+on: push
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+    - uses: ./uses-nested-composite/composite_action2
+      with:
+        test_input_optional: Test
+    - run: |
+        echo "steps.composite.outputs.secret_output=$COMPOSITE_ACTION_ENV_OUTPUT"
+        [[ "${{env.COMPOSITE_ACTION_ENV_OUTPUT == 'my test value' }}" = "true" ]] || exit 1
+      shell: bash