[Agents] Minor clean

[Oxyjun]

Summary

Cleans up the Agents docs.

1. The overview directs attention to "Build a chat agent" straight away, rather than having it in the sidebar under Getting started. (Amplitude number shows a huge difference in page views between Overview and "Build a chat agent" page).
2. Added a new "Get started" page which includes the CLI instructions which were previously in the Overview page.
3. The "Prompt an AI model" has been placed as a link at the bottom of the "Get started" page (Amplitude number showed the average number of clicks for this option per day was 0.77 in the last 12 weeks).
4. Renamed the title from "Build Agents on Cloudflare" to "Cloudflare Agents".

Screenshots (optional)

Left: Current, right: this PR

Documentation checklist

• Is there a changelog entry (guidelines)? If you don't add one for something awesome and new (however small) — how will our customers find out? Changelogs are automatically posted to RSS feeds, the Discord, and X.
• The documentation style guide has been adhered to.
• If a larger change - such as adding a new page- an issue has been opened in relation to any incorrect or out of date information that this PR fixes.
• Files which have changed name or location have been allocated redirects.

[github-actions]

This pull request requires reviews from CODEOWNERS as it changes files that match the following patterns:

Pattern	Owners
/public/__redirects	@GregBrimble, @KianNH, @pedrosousa, @WalshyDev, @cloudflare/pcx-technical-writing
/src/content/docs/agents/	@irvinebroque, @rita3ko, @elithrar, @thomasgauvin, @threepointone, @cloudflare/pcx-technical-writing

[github-actions]

Preview URL: https://4d575780.preview.developers.cloudflare.com
Preview Branch URL: https://jun-agents-cleanup.preview.developers.cloudflare.com

Files with changes (up to 15)

Original Link	Updated Link
https://developers.cloudflare.com/agents/	https://jun-agents-cleanup.preview.developers.cloudflare.com/agents/
https://developers.cloudflare.com/agents/getting-started/get-started/	https://jun-agents-cleanup.preview.developers.cloudflare.com/agents/getting-started/get-started/
https://developers.cloudflare.com/agents/getting-started/build-a-chat-agent/	https://jun-agents-cleanup.preview.developers.cloudflare.com/agents/getting-started/build-a-chat-agent/
https://developers.cloudflare.com/agents/getting-started/prompting/	https://jun-agents-cleanup.preview.developers.cloudflare.com/agents/getting-started/prompting/
https://developers.cloudflare.com/agents/getting-started/testing-your-agent/	https://jun-agents-cleanup.preview.developers.cloudflare.com/agents/getting-started/testing-your-agent/
https://developers.cloudflare.com/agents/api-reference/agents-api/	https://jun-agents-cleanup.preview.developers.cloudflare.com/agents/api-reference/agents-api/
https://developers.cloudflare.com/agents/api-reference/calling-agents/	https://jun-agents-cleanup.preview.developers.cloudflare.com/agents/api-reference/calling-agents/
https://developers.cloudflare.com/agents/api-reference/http-sse/	https://jun-agents-cleanup.preview.developers.cloudflare.com/agents/api-reference/http-sse/
https://developers.cloudflare.com/agents/api-reference/store-and-sync-state/	https://jun-agents-cleanup.preview.developers.cloudflare.com/agents/api-reference/store-and-sync-state/

[github-actions]

This PR requires additional review attention because it affects the following areas:

Redirects

This PR changes current filenames or deletes current files. Make sure you have redirects set up to cover the following paths:

• /agents/getting-started/build-a-chat-agent/
• /agents/getting-started/prompting/