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-min-max-sizing.md

@@ -0,0 +1,63 @@
+---
+name: layout-min-max-sizing
+description: Setting minimum and maximum width and height with min-w, max-w, min-h, max-h
+---
+
+# Min & Max Sizing
+
+Utilities for constraining element dimensions with minimum and maximum width/height.
+
+## Usage
+
+### Min width
+
+```html
+<!-- Spacing scale -->
+<div class="min-w-24">min-w-24</div>
+<div class="min-w-64">min-w-64</div>
+
+<!-- Percentage -->
+<div class="min-w-full">min-w-full</div>
+<div class="min-w-3/4">min-w-3/4</div>
+
+<!-- Container scale -->
+<div class="min-w-sm">min-w-sm</div>
+<div class="min-w-xl">min-w-xl</div>
+
+<!-- Content-based -->
+<div class="min-w-min">min-content</div>
+<div class="min-w-max">max-content</div>
+<div class="min-w-fit">fit-content</div>
+<div class="min-w-auto">auto</div>
+
+<!-- Custom -->
+<div class="min-w-[220px]">Custom</div>
+```
+
+### Max width
+
+Use `max-w-<value>` with similar scales: spacing numbers, fractions (`max-w-1/2`), container sizes (`max-w-md`), `max-w-full`, `max-w-screen`, `max-w-min`, `max-w-max`, `max-w-fit`, `max-w-none`.
+
+### Min / Max height
+
+```html
+<div class="min-h-screen">At least full viewport height</div>
+<div class="min-h-0">Allow shrinking in flex</div>
+<div class="max-h-96 overflow-y-auto">Scrollable with max height</div>
+```
+
+## Key Points
+
+- min-w: spacing scale, fractions, container scale (3xs–7xl), `full`, `screen`, `min`, `max`, `fit`, `auto`
+- max-w: same options plus `none`
+- min-h / max-h: similar scales; `min-h-0` important for flex children to shrink
+- Viewport units: `min-w-screen`, `min-w-dvw`, `min-w-svw`, `min-w-lvw`
+- Container scale: `min-w-3xs` through `min-w-7xl` map to `--container-*` variables
+
+<!--
+Source references:
+- https://tailwindcss.com/docs/min-width
+- https://tailwindcss.com/docs/max-width
+- https://tailwindcss.com/docs/min-height
+- https://tailwindcss.com/docs/max-height
+-->