Add interactive Likert scale input for pendlers-style projects

[caitlon]

User Story

As an expert entering opinions in a Likert-scale project, I want a visual slider or button interface, so that I can quickly select my opinion without manually typing numbers.

Problem Statement

The pendlers case study uses Likert scale (0, 25, 50, 75, 100). Currently, experts must enter these as crisp fuzzy numbers (a=c=b). A dedicated Likert input would improve UX for this common use case.

Proposed Solution

1. Project schema already has scale_min and scale_max fields
2. Detect Likert-style projects (discrete scale points: 5 or 7 point scales)
3. Show visual input: buttons or slider with labels
4. Map selection to fuzzy number automatically

UI Options

Option A: Button Group

[ Strongly Disagree ] [ Disagree ] [ Neutral ] [ Agree ] [ Strongly Agree ]
         0               25          50          75           100

Option B: Slider with labels

|-------|-------|-------|-------|
0      25      50      75     100

Acceptance Criteria

• Likert detection based on project settings (discrete scale)
• Visual input component (slider or button group)
• Labels configurable per project (e.g., "Strongly Disagree" to "Strongly Agree")
• i18n support for default labels (EN/CS)
• Accessible to keyboard/screen reader users
• Fallback to numeric input for non-Likert projects

Technical Notes

• Use Radix Slider or ToggleGroup components
• Store as fuzzy number with a=c=b (crisp)
• Consider adding likert_labels field to project schema