Add full CCSID via a unified getFileInfo component

## Feature Request: Unified `getFileInfo` Component for File Metadata with CCSID

### Summary
Create a new component that retrieves comprehensive file metadata including CCSID information in a single call for both IBM i source file members and IFS streamfiles, using appropriate IBM i APIs that expose CCSID and field-level attributes.

### Background

Currently, the extension retrieves file metadata through multiple separate API calls:
- **Member metadata**: `getMemberInfo()` via the `GETMBRINFO.SQL` component (wraps `QUSRMBRD`)
- **CCSID information**: `getAttributes()` using the PASE `attr` command for IFS files
- **Variant character handling**: Separate checks throughout the codebase

**Important limitation**: The current `QUSRMBRD` API used in `GETMBRINFO` does **not** return CCSID information for files or fields, which is critical for proper variant character handling.

This fragmented approach requires multiple round-trips to retrieve complete file information, and the lack of CCSID data at file-open time causes issues with variant character support.

### Proposed Solution

Create a new `getFileInfo` component that retrieves comprehensive file metadata in a single call, using the appropriate IBM i APIs:

#### Recommended API: `QUSLFLD` (List Fields)

**Primary recommendation**: Use the `QUSLFLD` API which:
- Returns all columns (fields) for a database file
- Includes **all field attributes including CCSID** for each field
- Is easier to implement than `QDBRTVFD`
- Provides consistent field-level metadata

**Alternative**: `QDBRTVFD` (Retrieve Database File Description)
- Returns both **File Format CCSID** and **individual field CCSID**
- More complex to implement but provides additional file-level information

#### Implementation Approach

**New SQL Component: `GETFILEINFO.SQL`**

Create a table function or stored procedure that wraps:
- `QUSLFLD` API for retrieving field information with CCSID attributes
- Continue using `QUSRMBRD` for member-level metadata (timestamps, description)
- For IFS files: Continue using PASE `attr` command for CCSID

**Suggested Return Type:**
```typescript
interface FileInfo {
// Member/File identification
library?: string;
file?: string;
name: string;
extension: string;
created?: Date;
changed?: Date;
description?: string;

// File-level attributes
ccsid: number; // File format CCSID
recordLength?: number; // For members/database files
fileType: 'member' | 'streamfile';
isSource: boolean;

// Field-level information (for database files)
fields?: Array<{
name: string;
type: string;
length: number;
decimal?: number;
ccsid?: number; // Field-specific CCSID
description?: string;
}>;

// For IFS files
path?: string;
size?: number;

// Additional metadata
asp?: string;
owner?: string;
}
```
This feature would particularly benefit external extensions that consume the Code for IBM i API and need to properly handle variant characters in syntax highlighting, code analysis, and transformation tools. The availability of CCSID information at file-open time is crucial for proper character encoding and variant character support throughout the IBM i development ecosystem.
Let me know if you want me to compose the wrapper for the QUSLFLD API for this feature of it is is no longer needed.