DX: Preflight Builds — snapshot working tree, push, trigger CI, watch results

[alexhraber]

Problem

The Buildkite CLI has an experimental bk preflight run command that snapshots your working tree (including unstaged/untracked changes), pushes to a temporary branch, triggers a CI build, and watches results — all before you commit. builddeck has no equivalent, meaning you have to context-switch to the CLI for this workflow.

Proposed Feature

A Preflight overlay (keybinding: ctrl+p or P) that:

1. Detects the local git repo (reads .git from CWD or a configurable path)
2. Shows a diff summary of uncommitted changes (files changed, insertions/deletions)
3. Offers to snapshot, push, and trigger a CI build on the selected pipeline
4. Watches the preflight build live in the existing TUI polling loop, with a special indicator ("PREFLIGHT" badge)
5. Cleans up the temp branch and optionally cancels the build on close

UX Flow

┌──────────────────────────────────────┐
│  ⚡ Preflight Build                    │
│                                       │
│  Working tree (2 files changed):      │
│  ┌───────────────────────────────┐    │
│  │ M src/handler.go  (+42 -12)   │    │
│  │ M tests/handler_test.go       │    │
│  │   (+8 -0)                     │    │
│  └───────────────────────────────┘    │
│                                       │
│  Target pipeline: my-pipeline         │
│  Branch:        preflight/<timestamp> │
│                                       │
│  [Cancel]  [Snap & Run]              │
└──────────────────────────────────────┘

Why this fits a TUI

• This is the CLI's most unique capability — bringing it into the TUI makes the TUI the one-stop CI control center
• The TUI already excels at watching build progress; preflight is a natural extension
• Engineers can fire off a preflight check without leaving their terminal dashboard
• Visual diff summary + live build watch is more informative than CLI output

Requirements

• Git repo detection: scan CWD, BUILDKITE_REPO env var, or ~/.config/builddeck/repo-path config
• Branch naming: preflight/builddeck-<timestamp>-<short-sha>
• Push requires remote git credentials (assume they are configured)
• Pipeline resolution: use current selected pipeline, or prompt
• Cleanup on close: delete remote branch, optionally cancel build

Risk

• Git push failure: if remote is unreachable or credentials missing, show clear error
• Long-running branch accumulation: cleanup must be reliable; optionally add cleanup command equivalent

References

• bk preflight run in buildkite/cli
• Preflight code maps repo/snapshot/git operations

Acceptance

• Preflight overlay opens with ctrl+p or P
• Shows unstaged/staged/untracked file summary
• Pre-fills pipeline from current selection
• Creates snapshot branch, pushes, triggers build
• Build is watched live in TUI with PREFLIGHT badge
• Cleanup on exit or manual close