Add the schulcloud CLI, and document the split

The CLI talks only to the Pi's /api surface and holds no Schulcloud
credential — only the same bearer token the Claude connector uses. That
is not layering for its own sake: a Schulcloud session dies after two
hours idle and a CLI process lives for seconds, so a CLI with its own
token would be dead most times you reached for it. Routing through the
Pi means one session, one keepalive, one monthly cookie paste.

sync is a one-way mirror, which follows from the data rather than from
scope-cutting: file records are immutable upstream, so there is no
versioning, no conflict resolution and no merge. State is keyed by file
record id with the path as derived output, so an upstream rename moves
the local file instead of duplicating it — verified against the live
server. Verification is size-only because the download endpoint exposes
no ETag and Schulcloud publishes no hash; size still catches the failure
that happens, a truncated download. Downloads land on a .part neighbour
and are renamed, so an interrupted run leaves no half-file that a later
run mistakes for complete. Deletions are reported but not propagated —
a teacher removing a worksheet is no reason to destroy the student's
copy — with --prune to opt in.

what_changed now clamps to the oldest stored generation instead of
refusing, and says it did: "what's new this week" is a reasonable
question to ask a two-day-old index.

Two build bugs caught by the checks rather than by luck: the smoke
harness constructed the app without services, so the index-backed tools
were never exercised; and the Docker build could not see
scripts/copy-assets.mjs, so the image would have shipped without
migrations and silently degraded to live-only.

67 unit tests (9 needing Postgres), smoke green both ways — 34 checks
with an index, 32 without, because graceful degradation is a supported
mode and not a fallback nobody runs.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

src/cli/client.ts

@@ -0,0 +1,94 @@
+import type { CliConfig } from './config.ts';
+
+/**
+ * Talks to the schulcloud-mcp server's /api surface.
+ *
+ * Deliberately the only thing in the CLI that knows a network exists, and it
+ * never touches Schulcloud directly — the Pi holds that credential.
+ */
+
+export interface ManifestEntry {
+	fileId: string;
+	name: string;
+	path: string;
+	size: number;
+	mimeType: string;
+	courseId: string | null;
+	courseTitle: string;
+	status: 'added' | 'unchanged' | 'removed';
+}
+
+export interface Manifest {
+	crawlId: number;
+	cursor: string;
+	crawledAt?: string;
+	count: number;
+	entries: ManifestEntry[];
+}
+
+export class ApiError extends Error {
+	readonly status: number;
+
+	constructor(status: number, message: string) {
+		super(message);
+		this.status = status;
+		this.name = 'ApiError';
+	}
+}
+
+export class ApiClient {
+	private readonly config: CliConfig;
+
+	constructor(config: CliConfig) {
+		this.config = config;
+	}
+
+	private async request(path: string, init: RequestInit = {}): Promise<Response> {
+		const response = await fetch(`${this.config.server}${path}`, {
+			...init,
+			headers: { ...(init.headers ?? {}), Authorization: `Bearer ${this.config.token}` },
+		});
+		if (!response.ok) {
+			let detail = '';
+			try {
+				const body = (await response.json()) as { message?: string; error?: string };
+				detail = body.message ?? body.error ?? '';
+			} catch {
+				// Non-JSON error bodies are not worth surfacing verbatim.
+			}
+			throw new ApiError(response.status, describe(response.status, detail, this.config.server));
+		}
+		return response;
+	}
+
+	async status(): Promise<Record<string, unknown>> {
+		return (await (await this.request('/api/status')).json()) as Record<string, unknown>;
+	}
+
+	async manifest(since?: string): Promise<Manifest> {
+		const query = since ? `?since=${encodeURIComponent(since)}` : '';
+		return (await (await this.request(`/api/manifest${query}`)).json()) as Manifest;
+	}
+
+	async refresh(courseId?: string, force = false): Promise<Record<string, unknown>> {
+		const response = await this.request('/api/refresh', {
+			method: 'POST',
+			headers: { 'content-type': 'application/json' },
+			body: JSON.stringify({ courseId, force }),
+		});
+		return (await response.json()) as Record<string, unknown>;
+	}
+
+	/** Streams one file's bytes. */
+	async file(fileId: string): Promise<Response> {
+		return this.request(`/api/files/${encodeURIComponent(fileId)}`);
+	}
+}
+
+function describe(status: number, detail: string, server: string): string {
+	if (status === 401) return `Unauthorized — the token is wrong or expired. Re-run: schulcloud login --server ${server} --token <token>`;
+	if (status === 503) return 'The server is running without an index, so this command is unavailable. Set DATABASE_URL on the server.';
+	if (status === 409) return detail || 'The sync cursor is unknown to the server. Run a full sync with --full.';
+	if (status === 429) return detail || 'Refreshed too recently — wait a moment, or pass --force.';
+	return detail ? `HTTP ${status}: ${detail}` : `HTTP ${status}`;
+}