feat: publish FreeRTOS C FC03 card

doc/assets/a1-context.puml

@@ -0,0 +1,19 @@
+@startuml
+!include card-uml-style.iuml
+scale 620 width
+top to bottom direction
+
+class "01  Hazard3 timer\nmtime · mtimecmp" as Timer <<hardware>>
+class "02  RV32I FreeRTOS port\nmachine-timer trap · tick hook" as Port <<boundary>>
+class "03  FreeRTOS scheduler\nReady lists · priorities · time slice" as Scheduler <<kernel>>
+class "04  C application tasks\npeerA · peerB · high probe · verifier" as Application <<application>>
+
+Timer --> Port : interrupt when mtime >= mtimecmp
+Port --> Scheduler : xTaskIncrementTick()
+Scheduler --> Application : select highest-priority Ready task
+
+note right of Port
+  Tick hook records bounded evidence only.
+  Application uses public task APIs.
+end note
+@enduml