docs(ia): rewrite Core Concepts landing page for style compliance

[ekline]

Summary

Persona context: This change addresses the highest-priority finding from a persona-scoped IA review of the Okteto docs. Three personas were evaluated: New Developer, Platform Engineer/Admin, and AI-Agent Developer. The Core Concepts landing page is the central architectural hub that all three personas pass through to understand Okteto's building blocks.

Top 3 findings from IA review:

Rank	Priority	Persona	Issue	Affected area	Proposed fix
1	High	All (esp. Platform Engineer)	Core Concepts landing page violates every style rule: banned opening phrase, 13 "Learn more →" links, marketing language	core/index.mdx	Rewrite with inline links, direct opening, proper terminology
2	High	New Developer	Developer quickstart is a dead end — only 3 outbound links, no path to CLI reference, Manifest, or Dev Environments	get-started/dev-quickstart.mdx	Add cross-links in a "Next steps" section
3	Medium	AI-Agent Developer	Agentic Workflows and Okteto AI sections are isolated islands — no inbound links from get-started or development pages	agentic/, okteto-ai/	Add cross-links from homepage, development landing, quickstart

What this PR fixes (finding #1)

The Core Concepts landing page (src/content/core/index.mdx) had these style violations:

• Banned opening phrase: "Before you start building with Okteto, it helps to understand..." (explicitly prohibited by voice-and-tone rules)
• 13 standalone "Learn more about X →" links (all banned by formatting rules — link text must be the subject of the link, embedded in a sentence)
• Meta-language description: "An overview of the core Okteto concepts..." (should be a functional sentence)
• Terminology issues: lowercase "namespace", "personal access tokens", "dev container settings"

Changes made:

• Replaced banned opening with a direct statement: "Okteto organizes development around isolated Namespaces, built-in networking, a remote Build Service, and a central manifest..."
• Converted all 13 standalone "Learn more →" links to inline links embedded in descriptive sentences
• Updated frontmatter description to a functional sentence
• Fixed Okteto terminology capitalization (Namespace, Personal Access Token, Development Container, Admin, etc.)
• Preserved all content, structure, and page organization — only the presentation changed

Remaining items (follow-up work)

• Finding Sample for working with npm link #2: Add cross-links from get-started/dev-quickstart.mdx to CLI reference, Okteto Manifest overview, and Development Environments section
• Finding document how to use a custom pipeline image #3: Add inbound links to Agentic Workflows and Okteto AI sections from the homepage, development landing, and quickstart pages

How to verify

1. Run yarn build from the docs/ directory — confirm no broken links or anchors
2. Start the dev server (yarn start) and navigate to Core Concepts in the sidebar
3. Walk the page as a Platform Engineer: can you reach every concept page from the inline links? Every link should be clickable within the descriptive sentence, not as a standalone "Learn more" line
4. Confirm the opening sentence directly describes what the section covers, with no preamble

ekline[bot] <202747777+ekline[bot]@users.noreply.github.com>

[netlify]

✅ Deploy Preview for okteto-docs ready!

Name	Link
🔨 Latest commit	1ebaac8
🔍 Latest deploy log	https://app.netlify.com/projects/okteto-docs/deploys/69f39a8114fad000085c3880
😎 Deploy Preview	https://deploy-preview-1232--okteto-docs.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.

---

To edit notification comments on pull requests, go to your Netlify project configuration.