chore: add CHANGELOG.md

[tupe12334]

Summary

This repo has no CHANGELOG.md. This PR adds one, covering the project's history to date using the Keep a Changelog format (https://keepachangelog.com/en/1.1.0/), grouped under a single [Unreleased] section since no tags/releases exist yet.

Entries are drawn from the merged PR history (since repo inception on 2026-02-19), filtering out pure lint/eslint-rule chores, dependency bumps, and bookkeeping/snapshot-only commits.

Added

• Add API versioning for the /open URL scheme (feat: add API versioning for /open URL scheme #27)
• Auto-close the /open page after 10 seconds, with a persistent toggle to disable it (feat: auto-close /open page after 10s with persistent toggle #26)
• Set up a CI/CD pipeline to deploy the site to Cloudflare Pages (Close centy issue #7: CI/CD pipeline deploy to Cloudflare Pages #25)
• Add support for GitLab issue URLs (feat: add GitLab issue URL support #24)
• Add logo and favicon (Close centy issue #15: Add logo and favicon #18)
• Add a Hooks section documenting pre:open and post:open config options (Add Hooks section: document pre:open and post:open config options #11)
• Add mobile-responsive layout and mobile e2e tests (Add mobile-responsive layout and mobile e2e tests (#17) #8)
• Add a GitHub Action setup section to the landing page (Add GitHub Action setup section to landing page #7)

Changed

• Replace inline SVG icons with the lucide-react icon library (Close centy issue #20: replace inline SVG icons with lucide-react #22)
• Update download buttons to link to GitHub releases (Update download buttons to link to GitHub releases #5)

Fixed

• Use path-based versioning (/v2/open) instead of a query parameter (?v=2) (fix: use path-based versioning (/v2/open) not query param (?v=2) #28)
• Fix incorrect GitHub Action reference: worktree-io/action to worktree-io/comment-action (Fix action name: worktree-io/action → worktree-io/comment-action #16)

Test plan

• Reviewed against gh pr list --state merged history for accuracy and PR numbering
• Diff limited to CHANGELOG.md only

cc @tupe12334

This pull request was opened by the CHANGELOG.md keeper (owned repos + my orgs) routine of moadim.