feat(common): Auto-generate complete-values-structure.yaml with objectname normalization (#44955)

Adds automated generation of `complete-values-structure.yaml` that
aggregates all chart configurations into a normalized reference
structure using placeholder values and `objectname` for variable-keyed
nested objects.

## Implementation

**Script:** `generate_complete_values_structure.py`
- Collects 841+ values.yaml files from stable/incubator charts and
common-test
- Merges into comprehensive structure showing all possible configuration
keys
- Preserves existing comments via ruamel.yaml (falls back to PyYAML with
warning)
- Applies normalization post-merge

**Normalization:**
- Variable-named keys → `objectname` placeholder
- String values → `""`
- Large numbers → `0` (preserves 0-100 as likely config values)
- Booleans → unchanged
- Lists → first element only (structure example)

**Parent keys with variable children:**
```python
PARENT_KEYS_WITH_VARIABLE_CHILDREN = {
    'workload', 'service', 'persistence', 'configmap', 'secret',
    'ingress', 'route', 'containers', 'initContainers', 'ports', 'hosts'
}
```

## Result

File reduced from 14k to 6.5k lines. Example structure:

```yaml
workload:
  objectname:  # replaces: main, backup, worker, etc.
    enabled: true
    type: ''
    podSpec:
      containers:
        objectname:  # replaces: main, sidecar, init, etc.
          enabled: true
          imageSelector: ''

service:
  objectname:  # replaces: main, api, metrics, etc.
    enabled: true
    ports:
      objectname:  # replaces: main, http, grpc, etc.
        port: 0
        protocol: ''
```

## Workflow Integration

Added to schema-validation job in `.github/workflows/common-tests.yaml`:
- Installs `ruamel.yaml` alongside PyYAML
- Runs before `test_schema.py`
- Comments persist across regenerations

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.github/workflows/common-tests.yaml

@@ -156,6 +156,13 @@ jobs:
         with:
           python-version: "3.10"
 
+      - name: Install Python dependencies
+        run: pip install PyYAML ruamel.yaml
+
+      - name: Generate complete values structure
+        run: |
+          python3 charts/library/common/generate_complete_values_structure.py
+
       - name: Run schema validation
         run: |
           python3 charts/library/common/test_schema.py --max-failures 0 --output-file stable_schema_validation.log