Add optional password strength indicator to dile-password component

[Copilot]

Adds real-time password strength visualization with color-coded progress bar and text label.

Changes

• New property: showStrength (boolean, default: false) - opt-in to preserve backward compatibility
• Strength algorithm: Scores 0-4 based on length (8+, 12+) and character variety (lowercase, uppercase, digits, special chars)
• Visual feedback: Animated progress bar with 4 levels (Weak/Fair/Good/Strong) using distinct colors (red/orange/blue/green)
• Styling: CSS custom properties for label customization (--dile-password-strength-label-font-size, --dile-password-strength-label-color)
• Performance: Static getters for constant arrays to avoid per-keystroke allocations

Usage

<dile-password 
  label="Password" 
  showStrength>
</dile-password>

Visual

Implementation Notes

Strength calculation maps raw score (0-6) to normalized levels (0-4) via 1.5x normalization factor. Indicator only renders when showStrength=true and password is non-empty. Extends DileInput's styles array to preserve base component styling.

---

💬 We'd love your input! Share your thoughts on Copilot coding agent in our 2 minute survey.