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/limits/src/__tests__/LimitSpecificity.test.tsx

@@ -0,0 +1,66 @@
+/*
+ * 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 {calculateSpecificity, compareSpecificity} from '@fluxer/limits/src/LimitSpecificity';
+import {describe, expect, test} from 'vitest';
+
+describe('LimitSpecificity', () => {
+	test('calculateSpecificity returns 0 for undefined filters', () => {
+		expect(calculateSpecificity(undefined)).toBe(0);
+	});
+
+	test('calculateSpecificity returns 0 for empty filters', () => {
+		expect(calculateSpecificity({})).toBe(0);
+	});
+
+	test('calculateSpecificity counts traits', () => {
+		expect(calculateSpecificity({traits: ['premium']})).toBe(1);
+		expect(calculateSpecificity({traits: ['premium', 'verified']})).toBe(2);
+	});
+
+	test('calculateSpecificity counts guild features', () => {
+		expect(calculateSpecificity({guildFeatures: ['MORE_EMOJI']})).toBe(1);
+		expect(calculateSpecificity({guildFeatures: ['MORE_EMOJI', 'MORE_STICKERS']})).toBe(2);
+	});
+
+	test('calculateSpecificity counts combined traits and guild features', () => {
+		expect(calculateSpecificity({traits: ['premium'], guildFeatures: ['MORE_EMOJI']})).toBe(2);
+		expect(
+			calculateSpecificity({
+				traits: ['premium', 'verified'],
+				guildFeatures: ['MORE_EMOJI', 'MORE_STICKERS'],
+			}),
+		).toBe(4);
+	});
+
+	test('compareSpecificity returns negative when a is less specific', () => {
+		expect(compareSpecificity(undefined, {traits: ['premium']})).toBeLessThan(0);
+		expect(compareSpecificity({traits: ['premium']}, {traits: ['premium', 'verified']})).toBeLessThan(0);
+	});
+
+	test('compareSpecificity returns 0 when equal specificity', () => {
+		expect(compareSpecificity(undefined, undefined)).toBe(0);
+		expect(compareSpecificity({traits: ['premium']}, {traits: ['verified']})).toBe(0);
+	});
+
+	test('compareSpecificity returns positive when a is more specific', () => {
+		expect(compareSpecificity({traits: ['premium']}, undefined)).toBeGreaterThan(0);
+		expect(compareSpecificity({traits: ['premium', 'verified']}, {traits: ['premium']})).toBeGreaterThan(0);
+	});
+});