feat: sync open-source context and capsule removal

- remove legacy contexts surfaces from the app, MCP bridge, standalone server, and docs
- keep getContext and retrieveQueryContext while aligning the simplified graph-only contract
- harden dev startup migration behavior and disable the accidental chat surface in open source

Generated with Codex

src/tools/skills/deleteSkill.ts

@@ -0,0 +1,37 @@
+import { tool } from 'ai';
+import { z } from 'zod';
+import { deleteSkill } from '@/services/skills/skillService';
+import { eventBroadcaster } from '@/services/events';
+
+export const deleteSkillTool = tool({
+  description: 'Delete a skill by name.',
+  inputSchema: z.object({
+    name: z.string().describe('The name of the skill to delete'),
+  }),
+  execute: async ({ name }) => {
+    try {
+      const result = deleteSkill(name);
+      if (!result.success) {
+        return {
+          success: false,
+          error: result.error,
+          data: null,
+        };
+      }
+
+      eventBroadcaster.broadcast({ type: 'GUIDE_UPDATED', data: { name } });
+
+      return {
+        success: true,
+        data: { name },
+        message: `Skill "${name}" deleted`,
+      };
+    } catch (error) {
+      return {
+        success: false,
+        error: error instanceof Error ? error.message : 'Failed to delete skill',
+        data: null,
+      };
+    }
+  },
+});