Add TTD attach to running process support in record dialog

[Copilot]

This PR implements support for attaching TTD (Time Travel Debugging) recording to running processes, addressing a key limitation mentioned in the documentation.

Changes Made

UI Enhancements

• Added radio button selection between "Launch new process" and "Attach to running process" modes
• Organized settings into grouped sections that enable/disable based on selected mode
• Integrated process selection using the existing AttachProcessDialog for consistent UX
• Added validation to ensure proper configuration before starting recording

Command Generation

The TTD command line generation now supports both modes:

• Launch mode: TTD.exe -accepteula -out "dir" [-tracingOff -recordMode Manual] -launch "exe" args
• Attach mode: TTD.exe -accepteula -out "dir" -attach PID

Process Selection

• Reuses the existing attach process dialog for familiar interface
• Displays selected process as "PID: XXXX" in a read-only field
• Validates that a process is selected before allowing recording to start

Validation & Error Handling

• Pre-validates all inputs before executing TTD.exe
• Mode-specific validation (executable path for launch, process selection for attach)
• Clear error messages for invalid configurations
• Proper handling of edge cases like paths with spaces

Documentation Updates

• Updated docs/guide/dbgeng-ttd.md to reflect new attach capability
• Removed the limitation statement about not supporting attach to running processes
• Added comprehensive documentation for both recording modes

UI Layout

The new dialog presents a clean interface with mode selection at the top, followed by grouped settings that are contextually enabled:

┌─────────────────── TTD Record ───────────────────┐
│ ◉ Launch new process                             │
│ ○ Attach to running process                      │
│                                                  │
│ ┌─── Launch Settings ─────────────────────────┐  │
│ │ [Executable path, working dir, arguments]   │  │
│ └─────────────────────────────────────────────┘  │
│                                                  │
│ ┌─── Attach Settings ─────────────────────────┐  │
│ │ [Process selection interface]               │  │
│ └─────────────────────────────────────────────┘  │
└──────────────────────────────────────────────────┘

This implementation maintains full backward compatibility while significantly expanding TTD recording capabilities for users who need to trace already running processes.

Fixes #600.

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