Show Launch Choices And Device Selection Reason

[drown0315]

Parent

#90

What to build

Extend Target App Launch Progress to show the launch choices that explain what
Flutter Pilot is starting. The launch panel should show the resolved Target
Device when one is known, explain whether it came from the user-provided
--device value or Scenario Recording auto-selection, and show flavor and
entrypoint when provided.

When Flutter Pilot intentionally lets Flutter choose its default device, the
panel should say Target Device: Flutter default rather than inventing a device
name. This preserves Flutter default behavior while making the device-selection
boundary visible.

Acceptance criteria

• Launch progress shows the resolved Target Device for explicit --device selections.
• Launch progress shows the original device selector as the selection reason for explicit --device selections.
• Launch progress shows the resolved Target Device for Scenario Recording auto-selection.
• Launch progress shows Selection: auto-selected for recording for recording-driven auto-selection.
• Launch progress shows Target Device: Flutter default when no Target Device was resolved and Flutter chooses the device.
• Launch progress shows flavor when --flavor is provided.
• Launch progress shows entrypoint when --target is provided.
• Omitted Target Device metadata, flavor, and entrypoint do not produce noisy placeholder lines beyond the intentional Flutter default device label.
• Tests cover explicit device selection, recording auto-selection, Flutter default, flavor display, and entrypoint display.

Blocked by

• Add Plain Target App Launch Progress #91