docs: Fix Quick Start setup flow issues

[BrianSeong99]

Context

From devrel#126 feedback by @Dominik1999.

Issues to fix

• Node.js version outdated: Expected output shows old versions, actual is v25.6.1 / 1.22.22
• PATH/zshrc: Should clarify ~/.zshrc vs nano ~/.zshrc for the PATH export step (also related to PATH not configured after midenup install stable on Ubuntu #181)
• midenup install stable output: Shows "No artifact found. Proceeding to install from source" which looks like errors
• Project creation redundancy: Quick Start creates my-test-project, but later pages ask to create a new project again. Should reuse the same project throughout
• miden client new-wallet confusion: "Deploy Your Account" step says miden client new-wallet but we already created a wallet — clarify the distinction
• miden client new-wallet config error: Old config files cause missing field 'remote_prover_timeout' — need better error message or docs note about deleting old config/sqlite
• miden client sync still needed?: Post-0.13, check if manual sync is still required and update accordingly