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-tables.md

@@ -0,0 +1,67 @@
+---
+name: layout-tables
+description: Table layout and border behavior with border-collapse, table-layout
+---
+
+# Table Layout
+
+Utilities for controlling table display, border behavior, and layout algorithm.
+
+## Usage
+
+### Border collapse
+
+```html
+<!-- Collapsed: adjacent borders merge into single border -->
+<table class="border-collapse border border-gray-400">
+  <thead>
+    <tr>
+      <th class="border border-gray-300 p-2">State</th>
+      <th class="border border-gray-300 p-2">City</th>
+    </tr>
+  </thead>
+  <tbody>
+    <tr>
+      <td class="border border-gray-300 p-2">Indiana</td>
+      <td class="border border-gray-300 p-2">Indianapolis</td>
+    </tr>
+  </tbody>
+</table>
+
+<!-- Separate: each cell has its own borders -->
+<table class="border-separate border border-gray-400">...</table>
+```
+
+### Table layout
+
+```html
+<!-- Auto: columns sized to content -->
+<table class="table-auto">...</table>
+
+<!-- Fixed: columns use first row widths -->
+<table class="table-fixed">...</table>
+```
+
+### Table display (from layout-display)
+
+Combine with `table`, `table-row`, `table-cell`, `table-header-group`, etc. for semantic table structure.
+
+### Responsive
+
+```html
+<table class="border-collapse md:border-separate">...</table>
+```
+
+## Key Points
+
+- `border-collapse` - adjacent borders merge (single border between cells)
+- `border-separate` - each cell displays its own borders
+- `table-auto` - column widths from content
+- `table-fixed` - fixed layout; first row sets column widths
+- In v4, `border-*` and `divide-*` default to `currentColor`; specify a color (e.g. `border-gray-200`) explicitly
+
+<!--
+Source references:
+- https://tailwindcss.com/docs/border-collapse
+- https://tailwindcss.com/docs/table-layout
+-->