feat(remote): paste clipboard images into remote terminals

[matej21]

Problem

Pasting a clipboard image into a remote-backed terminal was broken. TerminalPane::handle_paste wrote the image to the client's temp dir and sent that client-local path over the wire to the server's PTY — so the server-side process (e.g. Claude Code) got a path to a file that doesn't exist on it. Claude Code reads images by path, so this silently failed.

Local image paste already worked this way (write temp file → send_paste(path)); only the remote case was wrong.

Approach

Route remote image pastes over HTTP so the file is materialised where the terminal's process runs:

1. Client captures the clipboard image (GPUI ClipboardEntry::Image) and, when the terminal is remote, uploads the bytes to POST /v1/terminals/{id}/paste-image instead of writing a local temp file.
2. The server writes the bytes to its own temp dir and bracketed-pastes that path into the terminal — mirroring the local paste path, just across the wire — so the focused TUI's own paste handler attaches it.

Scope: remote desktop client (okena desktop connected to a remote okena server). Web/mobile clients are unchanged for now; they'd reuse the same endpoint via an onPaste handler.

Changes

• okena-views-terminal: ActionDispatch::upload_remote_paste_image (default no-op); handle_paste short-circuits to it for remote terminals.
• action_dispatch: strip the remote:{cid}: prefix and delegate to the connection manager.
• okena-remote-client: RemoteConnectionManager::upload_paste_image — fire-and-forget HTTP upload, mirrors send_action.
• remote server: new authenticated paste-image route (20 MiB body limit, overriding the global 1 MiB cap; clipboard PNGs routinely exceed 1 MiB) + RemoteCommand::PasteImage → ensure_terminal + send_paste on the GPUI thread.
• enable tokio fs feature for the async temp-file write.

Testing

• cargo clippy --workspace --all-targets -- -D warnings clean, cargo test green, CI passing.
• New unit tests for the MIME→extension mapping (param tolerance + default).

Notes

• Second commit (fix(lint)) is unrelated to this feature: the rust-toolchain.toml bump to 1.95.0 turned new clippy lints (collapsible_match, unnecessary_sort_by) into CI errors, which had already made main red. Mechanical, no behavior change — included here so this branch's CI is green; can be cherry-picked to main separately to un-red it sooner.
• TLS parity caveat: the upload mirrors send_action, which builds an http:// URL with a plain reqwest::Client (no cert pinning). So like every other action, image upload won't work over a TLS connection with a self-signed pinned cert — a pre-existing limitation of the action transport, not a new regression. Happy to fix both in a follow-up.

🤖 Generated with Claude Code