feat: add fluxer upstream source and self-hosting documentation

- Clone of github.com/fluxerapp/fluxer (official upstream)
- SELF_HOSTING.md: full VM rebuild procedure, architecture overview,
  service reference, step-by-step setup, troubleshooting, seattle reference
- dev/.env.example: all env vars with secrets redacted and generation instructions
- dev/livekit.yaml: LiveKit config template with placeholder keys
- fluxer-seattle/: existing seattle deployment setup scripts

fluxer/packages/sms/src/__tests__/TwilioSmsProvider.test.tsx

@@ -0,0 +1,112 @@
+/*
+ * Copyright (C) 2026 Fluxer Contributors
+ *
+ * This file is part of Fluxer.
+ *
+ * Fluxer is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Fluxer is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with Fluxer. If not, see <https://www.gnu.org/licenses/>.
+ */
+
+import {InvalidPhoneNumberError} from '@fluxer/errors/src/domains/auth/InvalidPhoneNumberError';
+import {createMockLogger} from '@fluxer/logger/src/mock';
+import {TwilioSmsProvider} from '@fluxer/sms/src/providers/TwilioSmsProvider';
+import {describe, expect, it} from 'vitest';
+
+interface TwilioRequest {
+	url: string;
+	authHeader: string;
+	body: string;
+}
+
+function getCapturedRequest(request: TwilioRequest | null): TwilioRequest {
+	if (!request) {
+		throw new Error('Expected Twilio request to be captured');
+	}
+	return request;
+}
+
+describe('TwilioSmsProvider', () => {
+	it('calls Twilio Verify start endpoint with expected payload', async () => {
+		let capturedRequest: TwilioRequest | null = null;
+
+		const fetchStub: typeof fetch = async (_input, init) => {
+			capturedRequest = {
+				url: String(_input),
+				authHeader: (init?.headers as Record<string, string>).Authorization,
+				body: init?.body as string,
+			};
+			return new Response(JSON.stringify({success: true}), {status: 200});
+		};
+
+		const provider = new TwilioSmsProvider({
+			config: {
+				accountSid: 'AC123',
+				authToken: 'twilio-secret',
+				verifyServiceSid: 'VA123',
+			},
+			logger: createMockLogger(),
+			fetchFn: fetchStub,
+		});
+
+		const phone = '+15551234567';
+		await provider.startVerification(phone);
+
+		const request = getCapturedRequest(capturedRequest);
+		expect(request.url).toBe('https://verify.twilio.com/v2/Services/VA123/Verifications');
+		expect(request.authHeader).toBe(`Basic ${Buffer.from('AC123:twilio-secret').toString('base64')}`);
+		expect(request.body).toContain('To=%2B15551234567');
+		expect(request.body).toContain('Channel=sms');
+	});
+
+	it('returns true when verification check is approved', async () => {
+		const provider = new TwilioSmsProvider({
+			config: {
+				accountSid: 'AC123',
+				authToken: 'twilio-secret',
+				verifyServiceSid: 'VA123',
+			},
+			logger: createMockLogger(),
+			fetchFn: async () => new Response(JSON.stringify({status: 'approved'}), {status: 200}),
+		});
+
+		const result = await provider.checkVerification('+15551234567', '123456');
+		expect(result).toBe(true);
+	});
+
+	it('returns false when verification check is rejected', async () => {
+		const provider = new TwilioSmsProvider({
+			config: {
+				accountSid: 'AC123',
+				authToken: 'twilio-secret',
+				verifyServiceSid: 'VA123',
+			},
+			logger: createMockLogger(),
+			fetchFn: async () => new Response(JSON.stringify({status: 'pending'}), {status: 200}),
+		});
+		expect(await provider.checkVerification('+15551234567', '123456')).toBe(false);
+	});
+
+	it('throws InvalidPhoneNumberError for Twilio invalid phone code', async () => {
+		const provider = new TwilioSmsProvider({
+			config: {
+				accountSid: 'AC123',
+				authToken: 'twilio-secret',
+				verifyServiceSid: 'VA123',
+			},
+			logger: createMockLogger(),
+			fetchFn: async () =>
+				new Response(JSON.stringify({code: 21211, message: 'Invalid To phone number'}), {status: 400}),
+		});
+		await expect(provider.startVerification('+15550000000')).rejects.toThrow(InvalidPhoneNumberError);
+	});
+});