feat(wallet): add remote-host handoff for wallet login and funding

[pejmanjohn]

This adds an explicit remote-host path for tempo wallet login and tempo wallet fund via --no-browser, plus the CLI, skill, and README guidance that remote agents need to hand the flow off to a user on another device.

OpenClaw-style agents run the CLI on one host while the human approves wallet actions from another device. Today the CLI already prints the auth URL/code, but the flow still defaults to opening a browser on the host and the narration stays same-machine oriented. This change makes that remote handoff a supported path without regressing the default local browser flow.

What changed:

• add --no-browser to tempo wallet login and tempo wallet fund
• print remote-safe handoff instructions for the no-browser paths while keeping the default local prompts unchanged
• document the remote branch in SKILL.md, README.md, and crates/tempo-wallet/README.md
• add black-box coverage for remote vs local login/funding behavior

This improves the CLI contract for remote-host agents, but it does not change wallet/auth backend semantics. If wallet creation still requires a second authorization round before the host is fully authorized, that follow-up still needs to be fixed outside this repo.

Verification:

• cargo fmt --all --check
• cargo clippy --workspace --all-targets --all-features --locked -- -D warnings
• cargo run -p tempo-wallet -- login --help
• cargo run -p tempo-wallet -- fund --help
• cargo test -p tempo-wallet --test remote_flows -- --nocapture
• RUSTDOCFLAGS='-D warnings' cargo doc --workspace --all-features --no-deps --locked
• cargo test --workspace --all-features --locked is flaky locally because payment::session::streaming::tests::submit_voucher_update_caches_head_unsupported_per_origin in tempo-request intermittently fails in the full suite while isolated reruns pass

[Slokh]

thanks for this, few comments

[Slokh]

@pejmanjohn can you lint / fmt / add changelog entry, thanks! lgtm to merge otherwise

[pejmanjohn]

@Slokh hopefully this addresses everything - if not lmk!

Pushed cd24f87 with the maintainer follow-up. This adds the required fork PR changelog fragment under .changelog/remote-wallet-no-browser.md and applies the nightly-rustfmt import regroup in login.rs that the fmt job was flagging. Fresh local verification on the merged branch: cargo clippy -p tempo-wallet --all-targets --all-features --locked -- -D warnings and cargo test -p tempo-wallet --all-features --locked.

[Slokh]

@pejmanjohn Looks good, I'll merge and do a 0.2.2 release for you, since we don't have any plans for changes in the next week.