feat(workflows): add label management utilities and CLI for workflows

- Introduced `label_manager.py` for consistent label operations across GitHub Issues and PRs
- Added `workflow_cli.py` for command-line interface to workflow utilities
- Updated `README.md` to document new modules and usage
- Enhanced `gen-preview.yml` to specify workflow names
- Added comprehensive unit tests for new functionalities

Author: MarkusNeusinger

.github/workflows/gen-preview.yml

@@ -3,7 +3,7 @@ run-name: "Preview: ${{ github.event.workflow_run.head_branch }}"
 
 on:
   workflow_run:
-    workflows: ["Plot Tests"]
+    workflows: ["CI: Plot Tests"]
     types:
       - completed
 

automation/scripts/README.md

@@ -0,0 +1,98 @@
+# Workflow Scripts
+
+Reusable Python utilities for GitHub Actions workflows.
+
+## Modules
+
+### `workflow_utils.py`
+Branch and issue parsing functions used across multiple workflows.
+
+```python
+from automation.scripts.workflow_utils import (
+    extract_branch_info,    # Parse auto/{spec-id}/{library} branches
+    extract_sub_issue,      # Extract sub-issue from PR body
+    extract_parent_issue,   # Extract parent issue with fallback
+    get_attempt_count,      # Count ai-attempt-X labels
+    parse_plot_path,        # Parse plots/{lib}/{type}/{spec}/{variant}.py
+    is_valid_library,       # Validate library name
+)
+```
+
+### `label_manager.py`
+Label operations and status transitions.
+
+```python
+from automation.scripts.label_manager import (
+    get_status_transition,  # Calculate label changes for status
+    get_quality_label,      # Get quality:* label for score
+    get_quality_transition, # Calculate quality label changes
+    is_approved,            # Check for ai-approved label
+    is_rejected,            # Check for ai-rejected label
+    get_current_status,     # Get current status from labels
+    LabelChange,            # Dataclass with to_gh_args() method
+)
+```
+
+### `workflow_cli.py`
+CLI interface for use in GitHub Actions shell steps.
+
+## Usage in Workflows
+
+### Option 1: Direct CLI (Recommended)
+
+```yaml
+- name: Extract branch info
+  id: branch_info
+  run: |
+    INFO=$(uv run python -m automation.scripts.workflow_cli extract-branch "$BRANCH")
+    echo "spec_id=$(echo $INFO | jq -r '.spec_id')" >> $GITHUB_OUTPUT
+    echo "library=$(echo $INFO | jq -r '.library')" >> $GITHUB_OUTPUT
+
+- name: Get attempt count
+  id: attempts
+  run: |
+    LABELS=$(gh pr view $PR_NUM --json labels -q '.labels[].name' | tr '\n' ',')
+    COUNT=$(uv run python -m automation.scripts.workflow_cli get-attempt-count "$LABELS")
+    echo "count=$COUNT" >> $GITHUB_OUTPUT
+
+- name: Update status labels
+  run: |
+    LABELS=$(gh pr view $PR_NUM --json labels -q '.labels[].name' | tr '\n' ',')
+    ARGS=$(uv run python -m automation.scripts.workflow_cli status-transition "$LABELS" "testing")
+    if [ -n "$ARGS" ]; then
+      gh pr edit $PR_NUM $ARGS
+    fi
+```
+
+### Option 2: Inline Python
+
+```yaml
+- name: Extract sub-issue
+  id: sub_issue
+  run: |
+    SUB_ISSUE=$(uv run python -c "
+    from automation.scripts.workflow_utils import extract_sub_issue
+    result = extract_sub_issue('''$PR_BODY''')
+    print(result if result else '')
+    ")
+    echo "number=$SUB_ISSUE" >> $GITHUB_OUTPUT
+```
+
+## CLI Commands
+
+| Command | Description | Example |
+|---------|-------------|---------|
+| `extract-branch` | Parse auto branch | `extract-branch auto/scatter-basic/matplotlib` |
+| `extract-sub-issue` | Get sub-issue from PR body | `extract-sub-issue "Sub-Issue: #42"` |
+| `extract-parent-issue` | Get parent issue | `extract-parent-issue "Parent: #100"` |
+| `get-attempt-count` | Count attempts | `get-attempt-count "ai-attempt-1,testing"` |
+| `parse-plot-path` | Parse plot file path | `parse-plot-path "plots/matplotlib/..."` |
+| `status-transition` | Get label change args | `status-transition "generating" "testing"` |
+| `quality-label` | Get quality label | `quality-label 95` |
+
+## Benefits
+
+1. **Testability** - 69 unit tests cover all functions
+2. **Consistency** - Same parsing logic across all workflows
+3. **Maintainability** - Fix bugs in one place
+4. **Documentation** - Clear docstrings and examples