🧪 test: add JWT secret rotation BDD scenarios and step implementations (#12)

✨ merge: implement JWT secret rotation with BDD scenario isolation

- Implement JWT secret rotation mechanism (closes #8)
- Add per-scenario state isolation for BDD tests (closes #14)
- Validate password reset workflow via BDD tests (closes #7)
- Fix port conflicts in test validation
- Add state tracer for debugging test execution
- Document BDD isolation strategies in ADR 0025
- Fix PostgreSQL configuration environment variables

Generated by Mistral Vibe.
Co-Authored-By: Mistral Vibe <vibe@mistral.ai>
Co-authored-by: Gabriel Radureau <arcodange@gmail.com>
Co-committed-by: Gabriel Radureau <arcodange@gmail.com>

features/greet/greet.feature

@@ -0,0 +1,37 @@
+# features/greet.feature
+@greet @smoke
+Feature: Greet Service
+  The greet service should return appropriate greetings
+
+  @basic
+  Scenario: Default greeting
+    Given the server is running
+    When I request the default greeting
+    Then the response should be "{\"message\":\"Hello world!\"}"
+
+  @basic
+  Scenario: Personalized greeting
+    Given the server is running
+    When I request a greeting for "John"
+    Then the response should be "{\"message\":\"Hello John!\"}"
+
+  @v2 @api
+  Scenario: v2 greeting with JSON POST request
+    Given the server is running with v2 enabled
+    When I send a POST request to v2 greet with name "John"
+    Then the response should be "{\"message\":\"Hello my friend John!\"}"
+
+  Scenario: v2 default greeting with empty name
+    Given the server is running with v2 enabled
+    When I send a POST request to v2 greet with name ""
+    Then the response should be "{\"message\":\"Hello my friend!\"}"
+
+  Scenario: v2 greeting with missing name field
+    Given the server is running with v2 enabled
+    When I send a POST request to v2 greet with invalid JSON "{}"
+    Then the response should be "{\"message\":\"Hello my friend!\"}"
+
+  Scenario: v2 greeting with name that is too long
+    Given the server is running with v2 enabled
+    When I send a POST request to v2 greet with name "ThisNameIsWayTooLongAndShouldFailValidationBecauseItExceedsTheMaximumAllowedLengthOf100Characters!!!!"
+    Then the response should contain error "validation_failed"