feat(snapshot): add CaptureHealth to surface partial capture state

Adds CaptureHealth{FailedSteps, Partial} to Snapshot. captureBrewList now propagates brew errors instead of swallowing them. CaptureWithProgress collects failed step names unconditionally (not gated on callback) and writes them to snap.Health. captureWithUI warns the user before save/upload when the snapshot is partial.

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-opencode)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

Author: fullstackjam

internal/snapshot/capture.go

@@ -115,6 +115,7 @@ func CaptureWithProgress(callback func(step ScanStep)) (*Snapshot, error) {
 	}
 
 	results := make([]interface{}, len(steps))
+	var failedSteps []string
 	for i, step := range steps {
 		if callback != nil {
 			callback(ScanStep{Name: step.name, Index: i, Total: len(steps), Status: "scanning", Count: 0})
@@ -123,12 +124,13 @@ func CaptureWithProgress(callback func(step ScanStep)) (*Snapshot, error) {
 		result, err := step.capture()
 		results[i] = result
 
-		if callback != nil {
-			if err != nil {
+		if err != nil {
+			failedSteps = append(failedSteps, step.name)
+			if callback != nil {
 				callback(ScanStep{Name: step.name, Index: i, Total: len(steps), Status: "error", Count: 0})
-			} else {
-				callback(ScanStep{Name: step.name, Index: i, Total: len(steps), Status: "done", Count: step.count(result)})
 			}
+		} else if callback != nil {
+			callback(ScanStep{Name: step.name, Index: i, Total: len(steps), Status: "done", Count: step.count(result)})
 		}
 	}
 
@@ -161,6 +163,10 @@ func CaptureWithProgress(callback func(step ScanStep)) (*Snapshot, error) {
 			Unmatched: []string{},
 			MatchRate: 0,
 		},
+		Health: CaptureHealth{
+			FailedSteps: failedSteps,
+			Partial:     len(failedSteps) > 0,
+		},
 	}, nil
 }
 
@@ -204,7 +210,6 @@ func isBrewInstalled() bool {
 	return err == nil
 }
 
-// captureBrewList runs a brew command and returns parsed output lines.
 func captureBrewList(args ...string) ([]string, error) {
 	if !isBrewInstalled() {
 		return []string{}, nil
@@ -213,7 +218,7 @@ func captureBrewList(args ...string) ([]string, error) {
 	cmd := exec.Command("brew", args...)
 	output, err := cmd.Output()
 	if err != nil {
-		return []string{}, nil
+		return []string{}, fmt.Errorf("brew %s: %w", args[0], err)
 	}
 
 	return parseLines(string(output)), nil

internal/snapshot/capture_test.go

@@ -1,9 +1,11 @@
 package snapshot
 
 import (
+	"errors"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 )
 
 // TestParseLines tests the parseLines function.
@@ -307,3 +309,56 @@ func TestParseVersion_EdgeCases(t *testing.T) {
 		})
 	}
 }
+
+func TestCaptureWithProgress_HealthTracksFailedSteps(t *testing.T) {
+	steps := []captureStep{
+		{
+			name:    "Step A",
+			capture: func() (interface{}, error) { return []string{"pkg"}, nil },
+			count:   func(v interface{}) int { return len(v.([]string)) },
+		},
+		{
+			name:    "Step B",
+			capture: func() (interface{}, error) { return []string{}, errors.New("simulated failure") },
+			count:   func(v interface{}) int { return 0 },
+		},
+		{
+			name:    "Step C",
+			capture: func() (interface{}, error) { return []string{"other"}, nil },
+			count:   func(v interface{}) int { return len(v.([]string)) },
+		},
+	}
+
+	results := make([]interface{}, len(steps))
+	var failedSteps []string
+	for i, step := range steps {
+		result, err := step.capture()
+		results[i] = result
+		if err != nil {
+			failedSteps = append(failedSteps, step.name)
+		}
+	}
+
+	require.Equal(t, []string{"Step B"}, failedSteps)
+	assert.True(t, len(failedSteps) > 0)
+}
+
+func TestCaptureWithProgress_HealthEmptyOnSuccess(t *testing.T) {
+	steps := []captureStep{
+		{
+			name:    "Step A",
+			capture: func() (interface{}, error) { return []string{"pkg"}, nil },
+			count:   func(v interface{}) int { return len(v.([]string)) },
+		},
+	}
+
+	var failedSteps []string
+	for _, step := range steps {
+		_, err := step.capture()
+		if err != nil {
+			failedSteps = append(failedSteps, step.name)
+		}
+	}
+
+	assert.Empty(t, failedSteps)
+}

internal/snapshot/snapshot.go

@@ -2,6 +2,11 @@ package snapshot
 
 import "time"
 
+type CaptureHealth struct {
+	FailedSteps []string `json:"failed_steps"`
+	Partial     bool     `json:"partial"`
+}
+
 type Snapshot struct {
 	Version       int             `json:"version"`
 	CapturedAt    time.Time       `json:"captured_at"`
@@ -13,6 +18,7 @@ type Snapshot struct {
 	DevTools      []DevTool       `json:"dev_tools"`
 	MatchedPreset string          `json:"matched_preset"`
 	CatalogMatch  CatalogMatch    `json:"catalog_match"`
+	Health        CaptureHealth   `json:"health"`
 }
 
 type PackageSnapshot struct {

internal/snapshot/snapshot_test.go

@@ -357,6 +357,26 @@ func TestSnapshot_CatalogMatchWithHighRate(t *testing.T) {
 	assert.Equal(t, 1.0, snap.CatalogMatch.MatchRate)
 }
 
+// TestCaptureHealth_DefaultIsHealthy verifies a zero-value CaptureHealth is not partial.
+func TestCaptureHealth_DefaultIsHealthy(t *testing.T) {
+	snap := &Snapshot{Version: 1}
+	assert.False(t, snap.Health.Partial)
+	assert.Empty(t, snap.Health.FailedSteps)
+}
+
+// TestCaptureHealth_PartialWhenStepsFail verifies Health reflects failed steps.
+func TestCaptureHealth_PartialWhenStepsFail(t *testing.T) {
+	snap := &Snapshot{
+		Health: CaptureHealth{
+			FailedSteps: []string{"Homebrew Formulae", "Homebrew Casks"},
+			Partial:     true,
+		},
+	}
+	assert.True(t, snap.Health.Partial)
+	assert.Equal(t, 2, len(snap.Health.FailedSteps))
+	assert.Contains(t, snap.Health.FailedSteps, "Homebrew Formulae")
+}
+
 // TestSnapshot_CatalogMatchWithLowRate tests catalog match with low match rate.
 func TestSnapshot_CatalogMatchWithLowRate(t *testing.T) {
 	snap := &Snapshot{