PR #28686 - manaflow-ai/cmux

Folds #26801, #26920 and #26921 into one PR, with their original commits kept (merged onto current feat-cmux-next, conflicts resolved in the merge commit). It stacks on #28111 (cloud.startChat first send), whose commits are in this branch until it lands; after that, an update-branch leaves only this PR's own diff (about 1,560 lines).

Leo: "where is everything cloud related? what are our goals, etc, why do we even have hundreds of things unmerged?" / "a lot of this stuff shouldn't require so much deliberation" / "are prs slowing us down or are they necessary / why dont we work on a big ol' branch".

What it does

#26801: Cloud is a row at the top of the environment picker's Cloud section, as where a new chat runs. Picking it drops a saved environment and refocuses the prompt. Sending runs cloud.startChat, which copies the folder the chip names to the person's Cloud machine and opens the chat there. A Cloud pick that isn't offered right now is refused and keeps the prompt. One start runs at a time from a page. The gallery has the two other designs beside the shipped row.
#26920: a new chat's run location defaults to where the newest chat in its folder ran. A carried-over Cloud is a default the folder may undo, and it doesn't change while a start is out.
#26921: a chat starting in Cloud shows its progress under the message (machine, folder, opening), using the design-token spacing. The host pushes each step to the page's card.

Why one PR, not three

The three are one stack, each built on the last. #26920's default reads the run mode #26801 adds, and #26921's card is fed from #26801's start. Landed apart, each would need its own rebase over 1,795 base commits and its own review of the same files. Together they are about 1,560 lines. The Auto row (#26940/#26941) is a real seam and goes in its own PR on top of this one.

Conflicts resolved against current base

App.tsx: base moved the NewTabScreen block above the history branch. onCloud, cloudStatus and cloudPickedNotOffered were ported to its new place, and the old-position block was dropped.
ComposerContext.tsx: kept base's waiting-machine face (waitingName) beside the Cloud face.
EnvironmentPicker.tsx: kept base's closeOnTrustAsk effect.
NewTabScreen.tsx: base's auth gate and command intercept come first in askChat, then Cloud. Kept base's plusRefused notice and folder strip.
CloudStartChat.swift: the progress report(...) sits before #28111's start.seed(cwd:), so the model still goes to the Cloud chat.
Localizable.xcstrings: base's table plus this PR's 10 keys (no duplicates).

Design spec

leo-workspace design/composer.md and design/environment-picker.md (rule 3). #28620 (This Mac's name) is a separate change on the same picker; where both touch the same files, both are kept.

Screenshots

The before/after screenshots (light and dark) are in #26801, #26920 and #26921. The UI is unchanged from those heads apart from the conflict resolution above.

Reds

Compared by test name against base. The 21-language string tables (112 missing in ActionCatalog/CmuxHome) are red on base too. The rest are noted in comments.

Agent session: agent session

🤖 Generated with Claude Code

^{Need help on this PR? Tag @codesmith-bot with what you need.}

Summary by cubic

Makes Cloud a run location for new chats, behind Labs: the environment picker's Cloud row makes the first send a cloud.startChat that copies the chat's folder to a Cloud machine and opens the chat there, with no machine, size, or environment prompt.

Start safety

A send is pinned to the machine and destination its first try took, so a retry reopens the same chat instead of duplicating it or overwriting its work.
The host picks this person's free machine, never the team's or lane-pool VMs; a new one is created under the send's key.
A first send that fails on a revoked OAuth token goes again once, 2 seconds later, on the chat's first turn only.
While a start is out, neither the composer nor the New Tab box takes anything — no typing, paste, file drop, or dictation — so nothing mid-start is lost when the tab closes on success.

Folder and progress

Only a folder inside the pane's roots is copied, each send into its own place under the work root; anything else is refused before the hold and gesture.
With Do not work in a project picked, a Cloud send names no folder and is refused before the hold ("Cloud isn't available for this chat") with the prompt kept, so the host never copies a repo the person declined.
A new chat's run location defaults to where its folder's newest chat ran — a Cloud start's own copy counts in that history — so a folder last run in Cloud opens new chats with Cloud picked until the folder undoes it.
A Cloud start shows its progress under the message (step, folder, machine, secrets, network) as the host pushes each step, in small-radius chips.