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-inset.md

@@ -0,0 +1,91 @@
+---
+name: layout-inset
+description: Controlling placement of positioned elements with top, right, bottom, left, and inset utilities
+---
+
+# Top / Right / Bottom / Left
+
+Utilities for controlling the placement of positioned elements.
+
+## Usage
+
+### Basic positioning
+
+Use `top-<number>`, `right-<number>`, `bottom-<number>`, `left-<number>` to position elements:
+
+```html
+<!-- Pin to top left corner -->
+<div class="relative size-32">
+  <div class="absolute top-0 left-0 size-16">01</div>
+</div>
+
+<!-- Span top edge -->
+<div class="relative size-32">
+  <div class="absolute inset-x-0 top-0 h-16">02</div>
+</div>
+
+<!-- Fill entire parent -->
+<div class="relative size-32">
+  <div class="absolute inset-0">05</div>
+</div>
+```
+
+### Inset utilities
+
+Use `inset-<number>` for all sides, `inset-x-<number>` for horizontal, `inset-y-<number>` for vertical:
+
+```html
+<div class="absolute inset-0">Fill parent</div>
+<div class="absolute inset-x-0 top-0">Span top</div>
+<div class="absolute inset-y-0 left-0">Span left</div>
+```
+
+### Negative values
+
+Prefix with a dash for negative values:
+
+```html
+<div class="relative size-32">
+  <div class="absolute -top-4 -left-4 size-14"></div>
+</div>
+```
+
+### Logical properties
+
+Use `start-<number>` and `end-<number>` for RTL-aware positioning:
+
+```html
+<div dir="ltr">
+  <div class="absolute start-0 top-0">Left in LTR</div>
+</div>
+<div dir="rtl">
+  <div class="absolute start-0 top-0">Right in RTL</div>
+</div>
+```
+
+### Percentage and custom values
+
+Use fractions for percentages or arbitrary values:
+
+```html
+<div class="absolute top-1/2 left-1/2 -translate-x-1/2 -translate-y-1/2">
+  Centered
+</div>
+<div class="absolute top-[117px] left-[20%]">
+  Custom position
+</div>
+```
+
+## Key Points
+
+- `inset-0` sets all sides to 0 (equivalent to `top-0 right-0 bottom-0 left-0`)
+- `inset-x-0` sets left and right to 0
+- `inset-y-0` sets top and bottom to 0
+- Use `start`/`end` for logical properties that adapt to text direction
+- Negative values use dash prefix: `-top-4`, `-left-8`
+- Combine with `position` utilities (`absolute`, `fixed`, `relative`, `sticky`)
+
+<!--
+Source references:
+- https://tailwindcss.com/docs/top-right-bottom-left
+-->