Add Invigorating Surge

[radar]

Summary

• Implements Invigorating Surge (Core Set 2021): instant, {1}{G}, "Put a +1/+1 counter on target creature you control, then double the number of +1/+1 counters on that creature."
• Targets only creatures controlled by the caster.
• Resolution adds one +1/+1 counter, then adds counters equal to the current count to double the total.

Test plan

• Targeting a creature with no counters results in 2 counters (1 added, doubled)
• Targeting a creature with 2 counters results in 6 counters (3 then doubled)
• Card only targets creatures controlled by the caster
• Full RSpec suite passes

Closes #200

Generated with Claude Code