fix: Update API Kit guide signing flow

[germartinez]

Context

This PR fixes:

• Fixes API Kit guide variables and signing flow
• Removes dotenv from Protocol Kit

[github-actions]

Overall readability score: 56.16 (🔴 -0.07)

File	Readability
api-kit.mdx	54.35 (🔴 -4.57)
protocol-kit.mdx	67.38 (🔴 -0.87)

View detailed metrics

🟢 - Shows an increase in readability
🔴 - Shows a decrease in readability

File	Readability	FRE	GF	ARI	CLI	DCRS
api-kit.mdx	54.35	43.32	11.87	12.8	11.89	7.4
	🔴 -4.57	🔴 -2.24	🔴 -0.91	🔴 -1.2	🔴 -0.41	🔴 -0.1
protocol-kit.mdx	67.38	56.96	9.36	10.1	11.36	6.84
	🔴 -0.87	🔴 -0.31	🔴 -0.11	🔴 -0.2	🔴 -0.17	🔴 -0.03

Averages:

	Readability	FRE	GF	ARI	CLI	DCRS
Average	56.16	48.97	10.78	12.64	12.35	7.58
	🔴 -0.07	🔴 -0.03	🔴 -0.01	🔴 -0.02	🔴 -0.01	🟢 +0

View metric targets

Metric	Range	Ideal score
Flesch Reading Ease	100 (very easy read) to 0 (extremely difficult read)	60
Gunning Fog	6 (very easy read) to 17 (extremely difficult read)	8 or less
Auto. Read. Index	6 (very easy read) to 14 (extremely difficult read)	8 or less
Coleman Liau Index	6 (very easy read) to 17 (extremely difficult read)	8 or less
Dale-Chall Readability	4.9 (very easy read) to 9.9 (extremely difficult read)	6.9 or less