build: package an executable war, and document runtime UI config

pom.xml

@@ -14,7 +14,18 @@
 	<groupId>com.lincfusion</groupId>
 	<artifactId>udyamlinc-backend</artifactId>
 	<version>0.0.1-SNAPSHOT</version>
-	<packaging>jar</packaging>
+	<!--
+		war, but still executable. spring-boot-maven-plugin repackages a war with
+		the provided-scope container under WEB-INF/lib-provided, so the one
+		artifact both runs with `java -jar` and deploys into a servlet container.
+		Nothing is given up by choosing war here.
+
+		If deploying into Tomcat rather than running it directly, that container
+		must be Tomcat 11+: Spring Boot 4 is Jakarta EE 11 / Servlet 6.1, and
+		Tomcat 9 (javax.*) cannot load it. Deploy the file as api#v1#udyam.war so
+		the container path matches the context path this app expects.
+	-->
+	<packaging>war</packaging>
 
 	<name>udyamlinc-backend</name>
 	<description>UdyamLinc — predictive cash-flow intelligence and early warning for rural microenterprises (NABARD Hackathon)</description>
@@ -31,6 +42,17 @@
 			<artifactId>spring-boot-starter-web</artifactId>
 		</dependency>
 
+		<!--
+			provided, so a servlet container supplies its own Tomcat instead of
+			the app carrying a second one into it. The repackaged war still holds
+			these under WEB-INF/lib-provided, so `java -jar` keeps working.
+		-->
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-tomcat</artifactId>
+			<scope>provided</scope>
+		</dependency>
+
 		<!-- Security -->
 		<dependency>
 			<groupId>org.springframework.boot</groupId>