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/layout-position.md

@@ -0,0 +1,85 @@
+---
+name: layout-position
+description: Controlling element positioning with static, relative, absolute, fixed, and sticky utilities
+---
+
+# Position
+
+Utilities for controlling how an element is positioned in the document.
+
+## Usage
+
+### Static positioning
+
+Use `static` to position an element according to the normal flow. Offsets are ignored and it won't act as a position reference for absolutely positioned children:
+
+```html
+<div class="static">
+  <p>Static parent</p>
+  <div class="absolute bottom-0 left-0">
+    <p>Absolute child</p>
+  </div>
+</div>
+```
+
+### Relative positioning
+
+Use `relative` to position an element in normal flow. Offsets are calculated relative to the element's normal position, and it acts as a position reference for absolutely positioned children:
+
+```html
+<div class="relative">
+  <p>Relative parent</p>
+  <div class="absolute bottom-0 left-0">
+    <p>Absolute child</p>
+  </div>
+</div>
+```
+
+### Absolute positioning
+
+Use `absolute` to position an element outside the normal flow. Neighboring elements act as if it doesn't exist. Offsets are calculated relative to the nearest positioned parent:
+
+```html
+<div class="relative">
+  <div class="absolute top-0 right-0">
+    <p>Absolute child</p>
+  </div>
+</div>
+```
+
+### Fixed positioning
+
+Use `fixed` to position an element relative to the browser window. Offsets are calculated relative to the viewport:
+
+```html
+<div class="fixed top-0 right-0 left-0">
+  <p>Fixed header</p>
+</div>
+```
+
+### Sticky positioning
+
+Use `sticky` to position an element as `relative` until it crosses a threshold, then treat it as `fixed` until its parent is off screen:
+
+```html
+<div>
+  <div class="sticky top-0">
+    <p>Sticky header</p>
+  </div>
+  <div>Content...</div>
+</div>
+```
+
+## Key Points
+
+- `static` is the default - elements flow normally
+- `relative` maintains normal flow but allows offsets and becomes a positioning context
+- `absolute` removes from flow and positions relative to nearest positioned ancestor
+- `fixed` positions relative to viewport, stays in place when scrolling
+- `sticky` combines relative and fixed behavior based on scroll position
+- Always use with offset utilities like `top-0`, `right-0`, `inset-0`, etc.
+
+<!--
+Source references:
+- https://tailwindcss.com/docs/position
+-->