refactor: rename agent group→application across entire codebase

Complete the group→application terminology rename in the agent
registry subsystem:

- AgentInfo: field group → application, all wither methods updated
- AgentRegistryService: findByGroup → findByApplication
- AgentInstanceResponse: field group → application (API response)
- AgentRegistrationRequest: field group → application (API request)
- JwtServiceImpl: parameter names group → application (JWT claim
  string "group" preserved for token backward compatibility)
- All controllers, lifecycle monitor, command controller updated
- Integration tests: JSON request bodies "group" → "application"
- Frontend: schema.d.ts, openapi.json, agent queries, AgentHealth

RBAC group references (groups table, GroupAdminController, etc.)
are NOT affected — they are a separate domain concept.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

cameleer3-server-app/src/main/java/com/cameleer3/server/app/security/JwtServiceImpl.java

@@ -60,13 +60,13 @@ public class JwtServiceImpl implements JwtService {
     }
 
     @Override
-    public String createAccessToken(String subject, String group, List<String> roles) {
-        return createToken(subject, group, roles, "access", properties.getAccessTokenExpiryMs());
+    public String createAccessToken(String subject, String application, List<String> roles) {
+        return createToken(subject, application, roles, "access", properties.getAccessTokenExpiryMs());
     }
 
     @Override
-    public String createRefreshToken(String subject, String group, List<String> roles) {
-        return createToken(subject, group, roles, "refresh", properties.getRefreshTokenExpiryMs());
+    public String createRefreshToken(String subject, String application, List<String> roles) {
+        return createToken(subject, application, roles, "refresh", properties.getRefreshTokenExpiryMs());
     }
 
     @Override
@@ -84,12 +84,12 @@ public class JwtServiceImpl implements JwtService {
         return validateAccessToken(token).subject();
     }
 
-    private String createToken(String subject, String group, List<String> roles,
+    private String createToken(String subject, String application, List<String> roles,
                                String type, long expiryMs) {
         Instant now = Instant.now();
         JWTClaimsSet claims = new JWTClaimsSet.Builder()
                 .subject(subject)
-                .claim("group", group)
+                .claim("group", application)
                 .claim("type", type)
                 .claim("roles", roles)
                 .issueTime(Date.from(now))
@@ -132,7 +132,7 @@ public class JwtServiceImpl implements JwtService {
                 throw new InvalidTokenException("Token has no subject");
             }
 
-            String group = claims.getStringClaim("group");
+            String application = claims.getStringClaim("group");
 
             // Extract roles — may be absent in legacy tokens
             List<String> roles;
@@ -145,7 +145,7 @@ public class JwtServiceImpl implements JwtService {
                 roles = List.of();
             }
 
-            return new JwtValidationResult(subject, group, roles);
+            return new JwtValidationResult(subject, application, roles);
         } catch (ParseException e) {
             throw new InvalidTokenException("Failed to parse JWT", e);
         } catch (JOSEException e) {