Phase 3: Skills & Context — skill system, personal context, context layering

Backend:
- Skill model + migration (with FK on chats.skill_id)
- Personal + general skill CRUD services with access isolation
- Admin skill CRUD endpoints (POST/GET/PATCH/DELETE /admin/skills)
- User skill CRUD endpoints (POST/GET/PATCH/DELETE /skills/)
- Personal context GET/PUT at /users/me/context
- Extended context assembly: primary + personal context + skill prompt
- Chat creation/update now accepts skill_id with validation

Frontend:
- Skill selector dropdown in chat header (grouped: general + personal)
- Reusable skill editor form component
- Admin skills management page (/admin/skills)
- Personal skills page (/skills)
- Personal context editor page (/profile/context)
- Updated sidebar: Skills, My Context nav items + admin skills link
- English + Russian translations for all skill/context UI

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/src/pages/admin/skills.tsx

@@ -0,0 +1,114 @@
+import { useState } from "react";
+import { Navigate } from "react-router-dom";
+import { useTranslation } from "react-i18next";
+import { useQuery, useMutation, useQueryClient } from "@tanstack/react-query";
+import { useAuthStore } from "@/stores/auth-store";
+import {
+  getGeneralSkills,
+  createGeneralSkill,
+  updateGeneralSkill,
+  deleteGeneralSkill,
+  type Skill,
+} from "@/api/skills";
+import { SkillEditor } from "@/components/admin/skill-editor";
+import { Plus, Pencil, Trash2, Sparkles } from "lucide-react";
+
+export function AdminSkillsPage() {
+  const { t } = useTranslation();
+  const user = useAuthStore((s) => s.user);
+  const queryClient = useQueryClient();
+  const [editing, setEditing] = useState<Skill | null>(null);
+  const [creating, setCreating] = useState(false);
+
+  if (user?.role !== "admin") return <Navigate to="/" replace />;
+
+  const { data: skills = [] } = useQuery({
+    queryKey: ["admin-skills"],
+    queryFn: getGeneralSkills,
+  });
+
+  const createMut = useMutation({
+    mutationFn: createGeneralSkill,
+    onSuccess: () => {
+      queryClient.invalidateQueries({ queryKey: ["admin-skills"] });
+      setCreating(false);
+    },
+  });
+
+  const updateMut = useMutation({
+    mutationFn: ({ id, ...data }: { id: string } & Record<string, string>) =>
+      updateGeneralSkill(id, data),
+    onSuccess: () => {
+      queryClient.invalidateQueries({ queryKey: ["admin-skills"] });
+      setEditing(null);
+    },
+  });
+
+  const deleteMut = useMutation({
+    mutationFn: deleteGeneralSkill,
+    onSuccess: () => queryClient.invalidateQueries({ queryKey: ["admin-skills"] }),
+  });
+
+  if (creating || editing) {
+    return (
+      <div className="max-w-2xl space-y-4">
+        <h1 className="text-2xl font-semibold">
+          {creating ? t("skills.create_general") : t("skills.edit_general")}
+        </h1>
+        <SkillEditor
+          skill={editing}
+          onSave={(data) =>
+            editing
+              ? updateMut.mutate({ id: editing.id, ...data })
+              : createMut.mutate(data)
+          }
+          onCancel={() => { setCreating(false); setEditing(null); }}
+          loading={createMut.isPending || updateMut.isPending}
+        />
+      </div>
+    );
+  }
+
+  return (
+    <div className="space-y-4">
+      <div className="flex items-center justify-between">
+        <h1 className="text-2xl font-semibold">{t("skills.general_skills")}</h1>
+        <button
+          onClick={() => setCreating(true)}
+          className="inline-flex h-9 items-center gap-2 rounded-md bg-primary px-4 text-sm font-medium text-primary-foreground hover:bg-primary/90 transition-colors"
+        >
+          <Plus className="h-4 w-4" /> {t("common.create")}
+        </button>
+      </div>
+
+      {skills.length === 0 && (
+        <p className="text-muted-foreground py-8 text-center">{t("skills.no_skills")}</p>
+      )}
+
+      <div className="space-y-2">
+        {skills.map((skill) => (
+          <div key={skill.id} className="flex items-center gap-3 rounded-lg border bg-card p-4">
+            <Sparkles className="h-5 w-5 text-primary shrink-0" />
+            <div className="flex-1 min-w-0">
+              <p className="font-medium">{skill.name}</p>
+              {skill.description && (
+                <p className="text-sm text-muted-foreground truncate">{skill.description}</p>
+              )}
+            </div>
+            <div className="flex gap-1">
+              <button onClick={() => setEditing(skill)} className="rounded p-2 hover:bg-accent transition-colors">
+                <Pencil className="h-4 w-4" />
+              </button>
+              <button
+                onClick={() => deleteMut.mutate(skill.id)}
+                className="rounded p-2 hover:bg-destructive/10 hover:text-destructive transition-colors"
+              >
+                <Trash2 className="h-4 w-4" />
+              </button>
+            </div>
+          </div>
+        ))}
+      </div>
+    </div>
+  );
+}