[docs] Replace insecure HTTP links with HTTPS in core documentation

# [docs] Replace insecure HTTP links with HTTPS in core documentation

Several non-local documentation links still use `http://` even though HTTPS should be preferred where supported. These are not local development URLs or SVG namespace declarations.

Checked against upstream `base/docs` HEAD:

```text
5735457f14fb940f749bbc0d0059128648c8c5b6
```

## Findings

- `docs/apps/builder-codes/app-developers.mdx:9`
- Current: `http://base.dev/`
- Suggested: `https://base.dev/`

- `docs/apps/builder-codes/app-developers.mdx:9`
- Current: `http://base.dev/`
- Suggested: `https://base.dev/`

- `docs/base-account/basenames/basenames-faq.mdx:28`
- Current: `http://coinbase.com/onchain-verify`
- Suggested: `https://coinbase.com/onchain-verify` or the current canonical Coinbase verification URL

- `docs/base-account/basenames/basenames-faq.mdx:33`
- Current: `http://basename.app`
- Suggested: `https://basename.app`

- `docs/base-account/basenames/basenames-faq.mdx:85`
- Current: `http://base.org/names`
- Suggested: `https://base.org/names`

- `docs/base-account/more/troubleshooting/usage-details/wallet-library-support.mdx:12`
- Current: `http://portal.thirdweb.com/connect`
- Suggested: `https://portal.thirdweb.com/connect`

- `docs/terms-of-service.mdx:114`
- Current: `http://docs.base.org/privacy-policy`
- Suggested: `https://docs.base.org/privacy-policy`

## Excluded from this report

- `http://localhost` and `http://127.0.0.1` development examples
- `http://www.w3.org/2000/svg` SVG namespace declarations

## Why this matters

Using HTTPS avoids insecure redirects, improves link hygiene, and prevents users from being sent to plaintext URLs when secure equivalents are available.