Fix skill deletion not persisting to database

The DELETE /api/skills/:id endpoint was removing the skill from the
in-memory object but saveSkills() only upserts — it never issues a SQL
DELETE. Use deleteCollectionItem() like agents, sessions, tasks, and
schedules already do.

Fixes #29

Author: waydelyle

src/app/api/skills/[id]/route.ts

@@ -1,5 +1,5 @@
 import { NextResponse } from 'next/server'
-import { loadSkills, saveSkills } from '@/lib/server/storage'
+import { loadSkills, saveSkills, deleteSkill } from '@/lib/server/storage'
 import { normalizeSkillPayload } from '@/lib/server/skills-normalize'
 
 export async function GET(_req: Request, { params }: { params: Promise<{ id: string }> }) {
@@ -35,7 +35,6 @@ export async function DELETE(_req: Request, { params }: { params: Promise<{ id:
   const { id } = await params
   const skills = loadSkills()
   if (!skills[id]) return new NextResponse(null, { status: 404 })
-  delete skills[id]
-  saveSkills(skills)
-  return NextResponse.json({ ok: true })
+  deleteSkill(id)
+  return NextResponse.json({ deleted: id })
 }

src/lib/server/storage.ts

@@ -464,6 +464,7 @@ export function deleteTask(id: string) { deleteCollectionItem('tasks', id) }
 export function deleteSession(id: string) { deleteCollectionItem('sessions', id) }
 export function deleteAgent(id: string) { deleteCollectionItem('agents', id) }
 export function deleteSchedule(id: string) { deleteCollectionItem('schedules', id) }
+export function deleteSkill(id: string) { deleteCollectionItem('skills', id) }
 
 // --- Queue ---
 export function loadQueue(): string[] {