feat(dispatch): implement dispatch-workflow.sh with dispatch, poll, and timeout

Add dispatch-workflow.sh script that dispatches a Gitea workflow
in another repository and polls synchronously for completion.
Refactor mock-api.sh to use Python3 HTTP server with sequence
support, enabling stateful poll-response simulation in tests.

tests/features/test-execution.feature

@@ -11,18 +11,18 @@ Feature: Test execution
   # Ticket 0002: dispatch-workflow.sh — Dispatching and polling workflows
   # ---------------------------------------------------------------------------
 
-  @ticket-0002 @mock @wip @real
+  @ticket-0002 @mock @real
   Scenario: Dispatch a test workflow and wait for its completion
     When a test workflow is dispatched to a test project
     Then the pipeline waits until the test workflow finishes
     And the pipeline continues only after receiving a success result
 
-  @ticket-0002 @mock @wip @real
+  @ticket-0002 @mock @real
   Scenario: Dispatch fails when the dispatched test workflow fails
     When a test workflow is dispatched and the tests fail
     Then the calling pipeline reports failure
 
-  @ticket-0002 @mock @wip
+  @ticket-0002 @mock
   Scenario: Dispatch times out when the test workflow takes too long
     When a test workflow is dispatched but does not finish within the allowed time
     Then the calling pipeline reports a timeout error