add builder codes overview page, fix agent builder codes guide and update sidebar

[roethke]

What changed? Why?

• Added an agent-developers.mdx overview page within Base chain docs with api/skill reference, link to guide and verification steps
• Made a few minor fixes to the agent-builder-codes.mdx page; fixed camelcase instead of snakecase, 4 steps instead of 3, wallet address in curl command listed as an array instead of a string
• Updated sidebar navigation

Notes to reviewers

How has it been tested?
Locally

[cb-heimdall]

✅ Heimdall Review Status

Requirement	Status	More Info
Reviews	✅ 1/1	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

[mintlify]

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Project	Status	Preview	Updated (UTC)
base	🟢 Ready	View Preview	Mar 31, 2026, 12:49 AM

[cb-heimdall]

Review Error for youssefea @ 2026-03-31 18:26:13 UTC
User failed mfa authentication, either user does not exist or public email is not set on your github profile. \ see go/mfa-help

[youssefea]

@roethke it might also make sense to update the "Products" section at get-started/base

Intead of Mini Apps, put AI Agents

Another suggestion is moving AI Agents to be the 3rd tab and push Mini Apps and OnchainKit to the far right, as they're just temporary migration pages at this point