docs: add "Coming from Ethereum" page for EVM/Solidity developers

[mehmetkr-31]

Closes #353

Summary

Adds a new get-started page, "Coming from Ethereum" (docs/builder/get-started/evm-developers.md), that maps familiar Ethereum/EVM/Solidity concepts to their Miden equivalents. The goal is to flatten the onboarding curve for the largest existing web3 developer audience.

The page contains:

1. The three big shifts — local execution + ZK proofs vs. global re-execution; note-based (UTXO-like) two-transaction transfers vs. account-based balance updates; privacy by default.
2. Concept mapping table — smart contract → account, mapping/state variables → storage slots & maps, ERC-20 → fungible faucet, transfer() → P2ID note, msg.sender → authentication component, eth_call → executeProgram, events → notes, etc.
3. Side-by-side code comparison — a Solidity ERC-20 transfer() next to the TypeScript web-client equivalent (client.transactions.send + consume), with the two-transaction model explained.
4. Smart contract differences — Rust → MASM, 255 storage slots + storage maps, no implicit msg.sender.
5. Where to go next — relative links to accounts, notes, read-storage, and smart-contracts.

Conventions followed

• sidebar_position: 6 in frontmatter only — the get-started sidebar is autogenerated, so no sidebars.ts change is needed.
• Only relative internal links; all four link targets verified to exist locally.
• Terminology and code style matched to the existing accounts.md / notes.md pages (e.g. "onchain", MidenClient.createTestnet(), the executeProgram ↔ eth_call analogy already used in the web-client docs).

Build note

npm run build fails locally on a pre-existing, unrelated issue: sidebars.ts references doc IDs that are ingested from external repos at CI time (rust-client, note-transport, bridging, tutorials/recipes, miden-bank, …), which don't exist in a fresh local clone. I verified the failure is identical on a clean main checkout, and that this new page (builder/get-started/evm-developers) is correctly discovered by the docs plugin. The full build should pass in CI where ingestion runs.

Happy to adjust the page title, placement (sidebar_position), or content scope if you'd prefer something different.

[chatgpt-codex-connector]

💡 Codex Review

Here are some automated review suggestions for this pull request.

Reviewed commit: 39a4539f35

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".

[chatgpt-codex-connector]

Define the note before consuming it

In this private-transfer example, the send call only destructures txId, but the next transaction consumes noteId, which is never declared or fetched. Readers copying this snippet will hit a runtime/reference error rather than learning the two-step flow; the example needs to either request/derive the created note ID (for example via the documented return/list path) and, for a private note, make it available to Bob through transport/import before calling consume.

Useful? React with 👍 / 👎.

[mehmetkr-31]

Fixed in 39d89a2 — the example is now split into two snippets: Tx 1 uses the documented returnNote: true path so the created note (and its ID) is defined, and Tx 2 shows Bob's client fetching the private note via client.notes.fetchPrivate() + listAvailable() before consume().

[mehmetkr-31]

Converted to draft: holding for maintainer confirmation on #353 (placement / title / assignment). The page is ready as a preview here — happy to adjust once a maintainer weighs in.