feat(api): REST-Endpunkte fuer Projekte, Notizen, Verbindungen und Sync

Alles, was die Oberflaeche kann, ist damit auch scriptbar:

  GET  POST           /api/projects
  GET  PATCH DELETE   /api/projects/:id
  POST                /api/projects/:id/sync
  GET  POST           /api/projects/:id/notes
  PATCH DELETE        /api/notes/:id
  GET  POST           /api/connections
  PATCH DELETE        /api/connections/:id
  POST                /api/connections/:id/check
  GET                 /api/connections/:id/repos
  GET                 /api/health

Details:
- Jede Eingabe laeuft durch Zod; Feldfehler kommen als Objekt zurueck, damit
  Formulare sie direkt anzeigen koennen.
- Beim Anlegen werden Owner und Repo-Name aus der URL abgeleitet, falls nicht
  explizit angegeben.
- Ein leeres Token-Feld beim Bearbeiten einer Verbindung laesst das
  gespeicherte Token unveraendert; null entfernt es.
- Verbindungsantworten enthalten nie das Chiffrat, nur einen Hinweis
  wie "ghp_...9f3a".
- /api/health prueft die Datenbank und dient dem Docker-Healthcheck.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

src/app/api/connections/[id]/check/route.ts

@@ -0,0 +1,31 @@
+import { NextResponse } from "next/server";
+import { prisma } from "@/lib/db";
+import { clientForConnection } from "@/lib/git";
+
+export const dynamic = "force-dynamic";
+
+type Params = { params: Promise<{ id: string }> };
+
+/** Testet Erreichbarkeit und Token einer Verbindung und merkt sich das Ergebnis. */
+export async function POST(_request: Request, { params }: Params) {
+  const { id } = await params;
+
+  const connection = await prisma.gitConnection.findUnique({ where: { id } });
+  if (!connection) {
+    return NextResponse.json({ error: "Verbindung nicht gefunden" }, { status: 404 });
+  }
+
+  const result = await clientForConnection(connection).check();
+
+  await prisma.gitConnection.update({
+    where: { id },
+    data: {
+      lastCheckedAt: new Date(),
+      lastCheckOk: result.ok,
+      lastCheckMessage: result.message,
+      username: result.user ?? connection.username,
+    },
+  });
+
+  return NextResponse.json(result, { status: result.ok ? 200 : 502 });
+}

src/app/api/connections/[id]/repos/route.ts

@@ -0,0 +1,28 @@
+import { NextResponse } from "next/server";
+import { prisma } from "@/lib/db";
+import { clientForConnection } from "@/lib/git";
+
+export const dynamic = "force-dynamic";
+
+type Params = { params: Promise<{ id: string }> };
+
+/** Listet Repositories, auf die der hinterlegte Token Zugriff hat. */
+export async function GET(request: Request, { params }: Params) {
+  const { id } = await params;
+  const query = new URL(request.url).searchParams.get("q") ?? undefined;
+
+  const connection = await prisma.gitConnection.findUnique({ where: { id } });
+  if (!connection) {
+    return NextResponse.json({ error: "Verbindung nicht gefunden" }, { status: 404 });
+  }
+
+  try {
+    const repos = await clientForConnection(connection).listRepos(query);
+    return NextResponse.json({ repos });
+  } catch (error) {
+    return NextResponse.json(
+      { error: error instanceof Error ? error.message : String(error) },
+      { status: 502 },
+    );
+  }
+}

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

@@ -0,0 +1,76 @@
+import { NextResponse } from "next/server";
+import { encryptSecret, tokenHint } from "@/lib/crypto";
+import { prisma } from "@/lib/db";
+import { normalizeBaseUrl } from "@/lib/git/http";
+import { connectionSafeSelect } from "@/lib/projects";
+import { connectionUpdateSchema, formatZodError } from "@/lib/validation";
+
+export const dynamic = "force-dynamic";
+
+type Params = { params: Promise<{ id: string }> };
+
+const safeSelect = {
+  ...connectionSafeSelect,
+  _count: { select: { projects: true } },
+};
+
+export async function PATCH(request: Request, { params }: Params) {
+  const { id } = await params;
+
+  let body: unknown;
+  try {
+    body = await request.json();
+  } catch {
+    return NextResponse.json({ error: "Ungueltiger JSON-Body" }, { status: 400 });
+  }
+
+  const parsed = connectionUpdateSchema.safeParse(body);
+  if (!parsed.success) {
+    return NextResponse.json(
+      { error: "Validierung fehlgeschlagen", fields: formatZodError(parsed.error) },
+      { status: 422 },
+    );
+  }
+
+  const data = parsed.data;
+  const update: Record<string, unknown> = {};
+  if (data.name !== undefined) update.name = data.name;
+  if (data.provider !== undefined) update.provider = data.provider;
+  if (data.baseUrl !== undefined) update.baseUrl = normalizeBaseUrl(data.baseUrl);
+  if (data.username !== undefined) update.username = data.username;
+
+  // token === null  -> Token entfernen
+  // token === ""    -> vom Schema zu null normalisiert
+  // token undefined -> unveraendert lassen
+  if (data.token !== undefined) {
+    if (data.token) {
+      update.tokenCipher = encryptSecret(data.token);
+      update.tokenHint = tokenHint(data.token);
+    } else {
+      update.tokenCipher = null;
+      update.tokenHint = null;
+    }
+  }
+
+  try {
+    const connection = await prisma.gitConnection.update({
+      where: { id },
+      data: update,
+      select: safeSelect,
+    });
+    return NextResponse.json({ connection });
+  } catch {
+    return NextResponse.json({ error: "Verbindung nicht gefunden oder Name vergeben" }, { status: 404 });
+  }
+}
+
+export async function DELETE(_request: Request, { params }: Params) {
+  const { id } = await params;
+  try {
+    // Projekte bleiben erhalten, connectionId wird per onDelete: SetNull geleert.
+    await prisma.gitConnection.delete({ where: { id } });
+    return NextResponse.json({ ok: true });
+  } catch {
+    return NextResponse.json({ error: "Verbindung nicht gefunden" }, { status: 404 });
+  }
+}