Default stream: parallel scan + stdout serialization (#8)

* feat(cmd): parallel default run with streaming scan

- Replace blocking scan+process with runRainDefaultStream (git-fire-style):
  cancellable scan, upsert/filter pipeline, FetchWorkers pool, atomic totals
- Per-repo output via runRainOnRepo with [N/M] headers and mutex-serialized blocks
- Scan progress ticker (2s), post-run TTY scan-wait or non-interactive cancel
- Tests: streaming integration, helper coverage, fetchFailureMessage/weather/outcome/buildKnownPaths/upsert

* fix(lint): silence Fprint* errcheck and drop unused printRainBranchResults

* fix(default stream): remove dead scan-wait block and sync ticker output

Drop unreachable post-worker scan prompt (scan always finishes before
repoChan closes). Serialize folder-progress lines with printMu like
worker output. Await scanDone before reading scanErr to avoid a race.

Co-authored-by: Ben Schellenberger <bschellenberger2600@users.noreply.github.com>

* fix: remove dead stdinInteractiveOK; serialize default-stream summary under printMu

Co-authored-by: Ben Schellenberger <bschellenberger2600@users.noreply.github.com>

---------

Co-authored-by: Cursor Agent <cursoragent@cursor.com>
Co-authored-by: Ben Schellenberger <bschellenberger2600@users.noreply.github.com>

Author: bschellenberger2600

cmd/root.go

@@ -692,14 +692,17 @@ func runRainDefaultStream(cfg *config.Config, reg *registry.Registry, regPath st
 	// walk is running, so long scans aren't silent. Skipped when DisableScan
 	// because there is no walk to report on.
 	var lastFolder atomic.Pointer[string]
+	var scanProgressTickerDone chan struct{}
 	if !opts.DisableScan {
 		go func() {
 			for p := range folderProgress {
 				pp := p
 				lastFolder.Store(&pp)
 			}
 		}()
+		scanProgressTickerDone = make(chan struct{})
 		go func() {
+			defer close(scanProgressTickerDone)
 			tick := time.NewTicker(2 * time.Second)
 			defer tick.Stop()
 			const scanPrefix = "   🔍 Scanning… "
@@ -790,11 +793,17 @@ func runRainDefaultStream(cfg *config.Config, reg *registry.Registry, regPath st
 	workersWG.Wait()
 	<-upsertDone
 	<-scanDone
+	if scanProgressTickerDone != nil {
+		<-scanProgressTickerDone
+	}
 
 	if scanErr != nil && !errors.Is(scanErr, context.Canceled) {
 		fmt.Fprintf(os.Stderr, "warning: scan error: %s\n", safety.SanitizeText(scanErr.Error()))
 	}
 
+	printMu.Lock()
+	defer printMu.Unlock()
+
 	if atomic.LoadInt64(&seq) == 0 {
 		fmt.Println("No git repositories found.")
 		return nil

go.mod

@@ -7,7 +7,7 @@ require (
 	github.com/charmbracelet/bubbletea v1.3.10
 	github.com/charmbracelet/lipgloss v1.1.0
 	github.com/git-fire/git-testkit v0.2.0
-	github.com/mattn/go-isatty v0.0.20
+	github.com/gofrs/flock v0.12.1
 	github.com/mattn/go-runewidth v0.0.19
 	github.com/pelletier/go-toml/v2 v2.2.4
 	github.com/spf13/cobra v1.10.2
@@ -26,9 +26,9 @@ require (
 	github.com/erikgeiser/coninput v0.0.0-20211004153227-1c3628e74d0f // indirect
 	github.com/fsnotify/fsnotify v1.9.0 // indirect
 	github.com/go-viper/mapstructure/v2 v2.4.0 // indirect
-	github.com/gofrs/flock v0.12.1 // indirect
 	github.com/inconshreveable/mousetrap v1.1.0 // indirect
 	github.com/lucasb-eyer/go-colorful v1.3.0 // indirect
+	github.com/mattn/go-isatty v0.0.20 // indirect
 	github.com/mattn/go-localereader v0.0.1 // indirect
 	github.com/muesli/ansi v0.0.0-20230316100256-276c6243b2f6 // indirect
 	github.com/muesli/cancelreader v0.2.2 // indirect

go.sum

@@ -89,17 +89,16 @@ github.com/xo/terminfo v0.0.0-20220910002029-abceb7e1c41e h1:JVG44RsyaB9T2KIHavM
 github.com/xo/terminfo v0.0.0-20220910002029-abceb7e1c41e/go.mod h1:RbqR21r5mrJuqunuUZ/Dhy/avygyECGrLceyNeo4LiM=
 go.yaml.in/yaml/v3 v3.0.4 h1:tfq32ie2Jv2UxXFdLJdh3jXuOzWiL1fo0bu/FbuKpbc=
 go.yaml.in/yaml/v3 v3.0.4/go.mod h1:DhzuOOF2ATzADvBadXxruRBLzYTpT36CKvDb3+aBEFg=
+golang.org/x/exp v0.0.0-20231006140011-7918f672742d h1:jtJma62tbqLibJ5sFQz8bKtEM8rJBtfilJ2qTU199MI=
+golang.org/x/exp v0.0.0-20231006140011-7918f672742d/go.mod h1:ldy0pHrwJyGW56pPQzzkH36rKxoZW1tw7ZJpeKx+hdo=
 golang.org/x/sys v0.0.0-20210809222454-d867a43fc93e/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.29.0 h1:TPYlXGxvx1MGTn2GiZDhnjPA9wZzZeGKHHmKhHYvgaU=
-golang.org/x/sys v0.29.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
 golang.org/x/sys v0.38.0 h1:3yZWxaJjBmCWXqhN1qh02AkOnCQ1poK6oF+a7xWL6Gc=
 golang.org/x/sys v0.38.0/go.mod h1:OgkHotnGiDImocRcuBABYBEXf8A9a87e/uXjp9XT3ks=
 golang.org/x/text v0.28.0 h1:rhazDwis8INMIwQ4tpjLDzUhx6RlXqZNPEM0huQojng=
 golang.org/x/text v0.28.0/go.mod h1:U8nCwOR8jO/marOQ0QbDiOngZVEBB7MAiitBuMjXiNU=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
-gopkg.in/check.v1 v1.0.0-20190902080502-41f04d3bba15 h1:YR8cESwS4TdDjEe65xsg0ogRM/Nc3DYOhEAlW+xobZo=
-gopkg.in/check.v1 v1.0.0-20190902080502-41f04d3bba15/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c h1:Hei/4ADfdWqJk1ZMxUNpqntNwaWcugrBjAiHlqqRiVk=
+gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c/go.mod h1:JHkPIbrfpd72SG/EVd6muEfDQjcINNoR0C8j2r3qZ4Q=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=