feat: publish FreeRTOS C FC06 card

doc/card-plan.md

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+# FC06 card plan
+
+## Thesis
+
+Software timer APIs enqueue commands. A dedicated FreeRTOS daemon updates timer
+lists and invokes callbacks later on its own task stack. Command acceptance is
+therefore not callback completion.
+
+## Evidence
+
+- both start commands accepted;
+- one-shot reset at tick 1 moves expiry to tick 6;
+- auto callbacks at ticks 2 and 4;
+- period change to three ticks produces the next callback at tick 7;
+- one-shot fires once, auto is stopped, daemon handle and stack differ from the
+  controller, and ten committed records produce a stable digest.