JWT Auth into V2 (#4187)

Merging JWT feature from main into V2

## Checklist

### General

- [ ] I have read the [Contribution
Guidelines](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/CONTRIBUTING.md)
- [ ] I have read the [Stirling-PDF Developer
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/DeveloperGuide.md)
(if applicable)
- [ ] I have read the [How to add new languages to
Stirling-PDF](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/HowToAddNewLanguage.md)
(if applicable)
- [ ] I have performed a self-review of my own code
- [ ] My changes generate no new warnings

### Documentation

- [ ] I have updated relevant docs on [Stirling-PDF's doc
repo](https://github.com/Stirling-Tools/Stirling-Tools.github.io/blob/main/docs/)
(if functionality has heavily changed)
- [ ] I have read the section [Add New Translation
Tags](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/HowToAddNewLanguage.md#add-new-translation-tags)
(for new translation tags only)

### UI Changes (if applicable)

- [ ] Screenshots or videos demonstrating the UI changes are attached
(e.g., as comments or direct attachments in the PR)

### Testing (if applicable)

- [ ] I have tested my changes locally. Refer to the [Testing
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/DeveloperGuide.md#6-testing)
for more details.

---------

Signed-off-by: dependabot[bot] <[email protected]>
Signed-off-by: stirlingbot[bot] <stirlingbot[bot]@users.noreply.github.com>
Co-authored-by: Ludy <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: EthanHealy01 <[email protected]>
Co-authored-by: Ethan <[email protected]>
Co-authored-by: Anthony Stirling <[email protected]>
Co-authored-by: stirlingbot[bot] <195170888+stirlingbot[bot]@users.noreply.github.com>
Co-authored-by: albanobattistella <[email protected]>

app/proprietary/build.gradle

@@ -1,9 +1,15 @@
 repositories {
     maven { url = "https://build.shibboleth.net/maven/releases" }
 }
+
+ext {
+    jwtVersion = '0.12.6'
+}
+
 bootRun {
     enabled = false
 }
+
 spotless {
         java {
         target 'src/**/java/**/*.java'
@@ -43,6 +49,8 @@ dependencies {
     api 'org.springframework.boot:spring-boot-starter-data-jpa'
     api 'org.springframework.boot:spring-boot-starter-oauth2-client'
     api 'org.springframework.boot:spring-boot-starter-mail'
+    api 'org.springframework.boot:spring-boot-starter-cache'
+    api 'com.github.ben-manes.caffeine:caffeine'
     api 'io.swagger.core.v3:swagger-core-jakarta:2.2.35'
     implementation 'com.bucket4j:bucket4j_jdk17-core:8.14.0'
 
@@ -52,6 +60,10 @@ dependencies {
     // implementation 'org.thymeleaf.extras:thymeleaf-extras-springsecurity5:3.1.3.RELEASE' // Removed - UI moved to React frontend
     api 'io.micrometer:micrometer-registry-prometheus'
     implementation 'com.unboundid.product.scim2:scim2-sdk-client:4.0.0'
+
+    api "io.jsonwebtoken:jjwt-api:$jwtVersion"
+    runtimeOnly "io.jsonwebtoken:jjwt-impl:$jwtVersion"
+    runtimeOnly "io.jsonwebtoken:jjwt-jackson:$jwtVersion"
     runtimeOnly 'com.h2database:h2:2.3.232' // Don't upgrade h2database
     runtimeOnly 'org.postgresql:postgresql:42.7.7'
     constraints {