Use Typer for argument parsing

[Copilot]

Migrates the CLI from argparse to Typer to simplify argument handling while preserving all existing functionality and maintaining backward compatibility.

Key Features Delivered

✅ Each arg is declared once - Using Annotated types and reusable option definitions
✅ Subcommands are supported - Multi-level subcommands working (aci get ids)
✅ Inline args or environment variables - --my-arg or MY_ARG="" both supported
✅ Interactive prompting - Missing required args prompt user automatically
✅ Help at all levels - --help works at main, subcommand, and sub-subcommand levels

Before (argparse)

$ c-aci-testing target create --help
usage: Utilities for testing workflows involving Confidential ACI. target [-h]

options:
  -h, --help  show this help message and exit

After (Typer)

$ c-aci-testing target create --help
Usage: c-aci-testing target create [OPTIONS] [TARGET_PATH]

 Create a new target.

╭─ Arguments ──────────────────────────────────────────────────────────────╮
│   target_path      [TARGET_PATH]  The relative path to the c-aci-testing │
│                                   target directory [default: /current]   │
╰──────────────────────────────────────────────────────────────────────────╯
╭─ Options ────────────────────────────────────────────────────────────────╮
│ --name  -n      TEXT  The name of the new target [default: example]      │
│ --help                Show this message and exit.                        │
╰──────────────────────────────────────────────────────────────────────────╯

Implementation Highlights

• Environment Variable Integration: Clear UI feedback showing [env var: REGISTRY] in help
• Interactive Prompting: Uses typer.prompt() for missing required arguments
• Rich Help Formatting: Proper command grouping with description boxes
• Key=Value Parameters: Custom parsing for --parameters key1=value1 key2=value2
• Backward Compatibility: Existing tests continue to work with old parameter functions
• Minimal Changes: Preserved all command names, argument structure, and behavior

Technical Details

• Added typer~=0.12.0 dependency
• Created new typer_parser.py with complete CLI implementation
• Updated main.py to use Typer instead of argparse
• Implemented custom key=value parsing equivalent to ExtendDictAction
• Preserved all existing parameter functions for test compatibility

All existing functionality works identically, but with improved user experience through better help formatting, environment variable visibility, and interactive prompting.

Fixes #137.

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