feat: add new OpenSpec skills for change management and onboarding

- Created `openspec-ff-change` skill for fast-forward artifact creation.
- Introduced `openspec-new-change` skill for structured change creation.
- Developed `openspec-onboard` skill for guided onboarding through OpenSpec workflow.
- Added `openspec-sync-specs` skill for syncing delta specs to main specs.
- Implemented `openspec-verify-change` skill for verifying implementation against change artifacts.
- Updated `.gitignore` to exclude OpenSpec generated files.
- Added `skills-lock.json` to manage skill dependencies.

.agents/skills/tailwindcss/references/core-preflight.md

@@ -0,0 +1,200 @@
+---
+name: core-preflight
+description: Understanding Tailwind's Preflight base styles and how to extend or disable them
+---
+
+# Preflight
+
+Preflight is Tailwind's opinionated set of base styles that smooth over cross-browser inconsistencies.
+
+## Overview
+
+Built on top of modern-normalize, Preflight is automatically injected when you import `tailwindcss`:
+
+```css
+@layer theme, base, components, utilities;
+
+@import "tailwindcss/theme.css" layer(theme);
+@import "tailwindcss/preflight.css" layer(base);
+@import "tailwindcss/utilities.css" layer(utilities);
+```
+
+## Key Resets
+
+### Margins Removed
+
+All default margins are removed from headings, paragraphs, blockquotes, etc:
+
+```css
+*,
+::after,
+::before {
+  margin: 0;
+  padding: 0;
+}
+```
+
+This prevents accidentally relying on browser default margins that aren't part of your spacing scale.
+
+### Border Styles Reset
+
+Borders are reset to make adding borders easier:
+
+```css
+*,
+::after,
+::before {
+  box-sizing: border-box;
+  border: 0 solid;
+}
+```
+
+Since the `border` utility only sets `border-width`, this ensures adding `border` always creates a solid `1px` border using `currentColor`.
+
+### Headings Unstyled
+
+All headings are unstyled by default:
+
+```css
+h1, h2, h3, h4, h5, h6 {
+  font-size: inherit;
+  font-weight: inherit;
+}
+```
+
+**Reasons:**
+- Avoids deviating from your type scale
+- In UI development, headings should often be visually de-emphasized
+
+### Lists Unstyled
+
+Ordered and unordered lists have no bullets or numbers:
+
+```css
+ol, ul, menu {
+  list-style: none;
+}
+```
+
+Style lists using utilities:
+
+```html
+<ul class="list-inside list-disc">
+  <li>One</li>
+  <li>Two</li>
+</ul>
+```
+
+**Accessibility:** Add `role="list"` for screen readers when keeping lists unstyled:
+
+```html
+<ul role="list">
+  <li>One</li>
+  <li>Two</li>
+</ul>
+```
+
+### Images Are Block-Level
+
+Images and replaced elements are `display: block`:
+
+```css
+img, svg, video, canvas, audio, iframe, embed, object {
+  display: block;
+  vertical-align: middle;
+}
+```
+
+Use `inline` utility if needed:
+
+```html
+<img class="inline" src="..." alt="..." />
+```
+
+### Images Are Constrained
+
+Images and videos are constrained to parent width:
+
+```css
+img, video {
+  max-width: 100%;
+  height: auto;
+}
+```
+
+Override with `max-w-none`:
+
+```html
+<img class="max-w-none" src="..." alt="..." />
+```
+
+### Hidden Attribute
+
+Elements with `hidden` attribute stay hidden:
+
+```css
+[hidden]:where(:not([hidden="until-found"])) {
+  display: none !important;
+}
+```
+
+## Extending Preflight
+
+Add base styles to the `base` layer:
+
+```css
+@layer base {
+  h1 {
+    font-size: var(--text-2xl);
+    font-weight: 600;
+  }
+  
+  h2 {
+    font-size: var(--text-xl);
+    font-weight: 600;
+  }
+  
+  a {
+    color: var(--color-blue-600);
+    text-decoration-line: underline;
+  }
+}
+```
+
+## Disabling Preflight
+
+Import Tailwind components individually, omitting Preflight:
+
+```css
+@layer theme, base, components, utilities;
+
+@import "tailwindcss/theme.css" layer(theme);
+/* @import "tailwindcss/preflight.css" layer(base); */ /* Omitted */
+@import "tailwindcss/utilities.css" layer(utilities);
+```
+
+## Working Around Third-Party Libraries
+
+Some libraries may conflict with Preflight. Override Preflight styles:
+
+```css
+@layer base {
+  .google-map * {
+    border-style: none;
+  }
+}
+```
+
+## Key Points
+
+- Preflight normalizes cross-browser inconsistencies
+- Margins, borders, headings, and lists are reset
+- Images are block-level and constrained by default
+- Extend Preflight with `@layer base`
+- Disable by omitting the preflight import
+- Override Preflight styles when needed for third-party libraries
+
+<!--
+Source references:
+- https://tailwindcss.com/docs/preflight
+-->