fix: correct step numbering, accessibility, and builder-code typo

[Pytkopff]

This PR consolidates fixes for multiple issues:

1. Fixed a logic error in "tokens-in-wallet.mdx" (restored missing Step 3).
2. Added missing alt-text to images for accessibility in "tokens-in-wallet.mdx".
3. Removed accidental extra whitespace in "builder-codes.mdx" (from previous commit).

[cb-heimdall]

🟡 Heimdall Review Status

Requirement	Status	More Info
Reviews	🟡 0/1	Denominator calculation Show calculation 1 if user is bot 0 1 if user is external 0 2 if repo is sensitive 0 From .codeflow.yml 1 Additional review requirements Show calculation Max 0 0 From CODEOWNERS 0 Global minimum 0 Max 1 1 1 if commit is unverified 0 Sum 1