[Formplayer] Add stopwatch/timer question type

[r0ssing]

Add a custom Stopwatch / Timer question type for ODE, focused on capturing elapsed time as a numeric response.

The control should allow users to measure and submit a duration, with the saved value stored as a double.

Potential display options:

• Stopwatch with Start, Pause, Resume, Reset, and Save/Confirm actions
• Countdown timer mode, where a configured duration counts down to zero
• Manual duration entry as a fallback or optional mode
• Large elapsed-time display for easy readability
• Compact mobile-friendly layout
• Optional lap/split display if supported by the data model

UX considerations:

• Clearly show the current elapsed or remaining time
• Prevent accidental reset while timing is active
• Make the saved value explicit before submission
• Support keyboard navigation and screen readers
• Work well on mobile and desktop
• Preserve existing validation and required-question behavior
• Render consistently in readonly/review mode
• Support translation of all user-facing text using standard ODE i18n/localization support
• Define the stored unit clearly, such as seconds as a double
• Handle paused, reset, incomplete, and already-saved states predictably

Implementation scope:

• Add the Stopwatch / Timer as a custom question type in ODE
• Store the captured duration as a double, preferably in a documented canonical unit
• Support configurable behavior such as stopwatch mode, countdown mode, manual entry, min/max duration, and precision
• Add a Storybook component for the control in formplayer
• Include stories for stopwatch mode, countdown mode, paused state, reset state, validation/error state, readonly state, translated labels, and mobile-friendly layouts
• Update relevant documentation to describe configuration options, saved value format, units, accessibility behavior, localization support, and example usage

Acceptance criteria:

• A Stopwatch / Timer question can be configured and rendered in ODE
• Users can start, pause/resume, reset, and save a duration
• The selected/captured duration is saved as a double in the documented unit
• Required-question and validation behavior works consistently
• Incomplete or unsaved timing states are handled clearly
• All user-facing text is translatable using existing ODE i18n support
• The control supports accessible labels, keyboard interaction, and visible focus states
• Storybook includes examples for the main timer states and variants
• Documentation is updated with usage guidance and examples