Sync generator templates toward ignition-sdk-examples (Fixes #70)

[sankalpsthakur]

Summary

Addresses #70: generated module skeletons had drifted from ignition-sdk-examples (8.3 line).

This is a high-value slice, not a full rewrite of multi-version support:

Item	Before	After	Notes
Ignition SDK / sdk_version	8.1.20	8.3.0	Matches examples requiredIgnitionVersion
Version catalog	template unused	written to gradle/libs.versions.toml	Hyphenated keys align with examples
Subproject deps	string-interpolated coords	compileOnly(libs.ignition.*)
Settings file	Groovy default even for Kotlin builds	settings DSL follows buildscript DSL	Kotlin → settings.gradle.kts
deepClean task	missing	present on root buildscripts	Matches examples cleanup helper
Gateway/Designer hooks	outdated 8.0-era APIs (javax.servlet, removed overview contributors)	minimal 8.3 lifecycle stubs	Generated projects compile against SDK 8.3
Language version	25 (from #75)	unchanged	Tools line already on JDK 25
Gradle wrapper default	9.3.1 (from #75)	unchanged	Multi-version wrappers kept
io.ia.sdk.modl version	1.0.0	unchanged	Repo version; examples still pin older releases

Intentional non-goals

• Did not force plugin version to 0.1.1 as listed in the issue (that is older than published 0.5.0 / in-repo 1.0.0).
• Did not drop older Gradle wrapper bundles (6.x/7.x); multi-version support remains.
• Did not change Java toolchain on generated projects back to 17 (IA already moved templates to 25 in Upgrade to Kotlin 2.3.10, Gradle 9.4 plugins, and JDK 25 toolchain  #75). Module authors can still set their own toolchain.

Validation

export JAVA_HOME=…/openjdk@25
./gradlew genTest
./gradlew pluginPublishToMavenLocal genPublishToMavenLocal

# Kotlin multi-scope (GCD) + Groovy single-scope (G) smoke:
# generate via CLI, add mavenLocal() to pluginManagement for unpublished 1.0.0 plugin,
# set skipModlSigning true, then:
./gradlew build   # BUILD SUCCESSFUL for both

AI disclosure

This change was prepared with assistance from an AI coding agent. The author reviewed the diff, ran generator unit tests and smoke builds of generated projects against Ignition SDK 8.3.0, and is responsible for the PR contents.

Fixes #70