task: De-promote thirdweb — keep one tool page at parity with other tools, drop code examples and recommendations

[GigaHierz]

Part of #2266.

What needs to be done?

Decided: thirdweb stays in the docs as a listed tool but is no longer promoted — no more prominent than Hardhat, Foundry, viem or any other tool, no tutorials, no "recommended" wording.

At bdf40b37 thirdweb appears in:

• 4 in-nav pages: tooling/dev-environments/thirdweb/{overview,thirdweb,one-click-deploy}.mdx, tooling/libraries-sdks/thirdweb-sdk/index.mdx
• 3 orphaned pages: build-on-celo/build-with-thirdweb/{overview,celo-nft-drop-tutorial}.mdx and build-on-celo/build-with-thirdweb/one-click quickstart.mdx (space in the filename; URL-encoded redirect source at docs.json:3151)
• a provider entry in tooling/wallets/index.mdx:92
• an "Alternative" section on build-on-celo/build-with-ai/x402.mdx
• 3 image assets (img/thirdweb.svg, img/thirdweb-explore.png, img/building/how-to-deploy/thirdweb/thirdweb-explore.png)
• a redirect chain at docs.json:1468 → /build/build-with-thirdweb/celo-nft-drop-tutorial, which is itself a redirect source (line 3147)

Definition of done

Code:

• The 7 pages collapsed into one neutral page: what it is, Celo chain configuration, link to thirdweb's own docs — same group and format as the other tools. OPEN: home it under dev-environments or under SDKs; pick one and apply the same choice to the redirects
• Tutorials, step-by-step code examples, and "recommended" / "easiest way" wording removed
• The 6 other paths redirect to the one page; one-click quickstart.mdx deleted
• Wallet-provider entry in tooling/wallets/index.mdx kept as a plain list item (parity with the other providers)
• x402 "Alternative" section reduced to one link
• Redirect chain at docs.json:1468 resolved
• Unused images removed
• npx mintlify broken-links green

Ops (separate, outside the repo):

• Follow-up tracked outside this repository.

Non-goals

Removing thirdweb entirely.

Depends on / blocks

Depends on #2252 (orphan-handling boundary — this ticket owns the 3 thirdweb orphans). Blocks #2259.

Measured at: bdf40b37

[GigaHierz]

Closing: the repository work shipped in #2291. Anything further is not a documentation task.