Feature: Dark Mode + README Overhaul

[SeanathanVT]

Feature: Dark Mode + README Overhaul

Summary

Adds a three-state dark mode toggle (Light → Dark → System) and completely rewrites the README for clarity, tone, and accuracy.

Changes

Dark Mode (templates/base.html)

• CSS custom properties for all colors with [data-theme="dark"] selector overrides using a slate-based dark palette
• Toggle button in the header with icon cycling: ☀️ Light → 🌙 Dark -> 💻 System
• localStorage persistence — user preference survives page reloads (key: walkingpad-theme)
• OS auto-follow — in System mode, listens for prefers-color-scheme changes and updates the theme without a refresh
• Smooth transitions on background-color and color properties (0.2s ease)
• Bootstrap .text-muted override for dark mode readability

README Rewrite (README.md)

• Reduced from 229 → 96 lines
• New tagline, tone, and structure aligned with modern GitHub README conventions
• Shoutout to original developer CodeJawn whose walkingpad app this was forked from
• Consolidated setup/installation/run into single Quick Start section
• Simplified usage, configuration table, and troubleshooting

ROADMAP Update (ROADMAP.md)

• Marked Phase 2.1 Dark Mode as ✅ Complete with implementation details
• Renumbered subsequent Phase 2 items (2.2 → 2.5)

Screenshots (screenshots/)

• Replaced all three screenshots (start.png, active.png, paused.png) with dark mode captures so the README accurately reflects what the app actually looks like now.

Changelog (CHANGELOG.md)

• New CHANGELOG.md created for the v1.0.0 release, documenting all added/changed/fixed items plus pre-release history from the original walkingpad app
• README updated with changelog reference section

Consistency & Polish

• Branding fix — Updated remaining references from "WalkingPad Controller" to "WalkingDad" in templates/base.html page title and start_app.bat window/console titles
• requirements.txt — Sorted dependencies alphabetically for consistency

Files Changed

File	Change
templates/base.html	+132 lines (dark mode CSS, toggle button, JS logic, branding fix)
README.md	Full rewrite (229 → 96 lines)
ROADMAP.md	+31 lines (Dark Mode completion note, renumbering)
start_app.bat	Branding: "WalkingPad Controller" → "WalkingDad"
requirements.txt	Alphabetical sort
CHANGELOG.md	New file — v1.0.0 release notes

Total: 6 files, 205 insertions, 216 deletions (excluding new CHANGELOG.md)

Testing

• Theme toggle cycles correctly: Light → Dark → System → Light...
• localStorage persists selection across page reloads
• System mode follows OS prefers-color-scheme changes in real time
• All UI elements remain readable in both light and dark themes
• README renders correctly on GitHub

Notes

No backend or BLE changes in this PR. All changes are frontend/template and documentation only.