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/fluxer_app/scripts/build/tsconfig.json

@@ -0,0 +1,24 @@
+{
+	"$schema": "https://json.schemastore.org/tsconfig",
+	"compilerOptions": {
+		"target": "ES2023",
+		"module": "ESNext",
+		"lib": ["ES2023"],
+		"noEmit": true,
+		"moduleResolution": "Bundler",
+		"moduleDetection": "force",
+		"resolveJsonModule": true,
+		"isolatedModules": true,
+		"verbatimModuleSyntax": true,
+		"jsx": "preserve",
+		"esModuleInterop": true,
+		"allowSyntheticDefaultImports": true,
+		"strict": true,
+		"skipLibCheck": true,
+		"forceConsistentCasingInFileNames": true,
+		"paths": {
+			"@app_scripts/*": ["./../*"]
+		}
+	},
+	"include": ["./**/*.ts", "./**/*.tsx"]
+}