v0.1.2

Released from tag v0.1.2 (c926446). Compared with 0.1.1:

• Apply the configured blocking-call timeouts to the builder-built DefaultRequestHandler
  (a2a-java hardcodes 5s and never consults A2AConfigProvider on the builder path) and raise
  A2AProperties defaults to agent=900s / consumption=960s / reconciliation=60s.
• Echo requested supported extensions via the A2A-Extensions response header on success
  responses, so extension-aware clients can verify server participation.
• Keep workbench notification subscriptions state-independent from workflow task sessions.

Published to Maven Central as net.openan.workflow.sdk:*:0.1.2
(spring-boot-starter,
workflow-engine,
parent).