test(sync): compare claude shadow parity

Claude is shadow-compared on this branch, so add source-level migration coverage that compares provider observation with ParseClaudeSessionWithExclusions.

The fixture exercises the project-directory source shape and verifies session, message, usage, exclusion, and data-version planning parity while preserving provider-computed file hashes.

Validation: go test -tags "fts5" ./internal/sync -run TestObserveProviderSourceMatchesClaudeLegacyParser -count=1

Author: mariusvniekerk

internal/sync/provider_shadow_claude_test.go

@@ -0,0 +1,59 @@
+package sync
+
+import (
+	"context"
+	"path/filepath"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"go.kenn.io/agentsview/internal/parser"
+	"go.kenn.io/agentsview/internal/testjsonl"
+)
+
+func TestObserveProviderSourceMatchesClaudeLegacyParser(t *testing.T) {
+	root := t.TempDir()
+	projectDir := "-Users-dev-code-demo"
+	sourcePath := filepath.Join(root, projectDir, "claude-shadow.jsonl")
+	writeProviderShadowSourceFile(t, sourcePath, claudeShadowFixture())
+
+	provider, ok := parser.NewProvider(parser.AgentClaude, parser.ProviderConfig{
+		Roots:   []string{root},
+		Machine: "devbox",
+	})
+	require.True(t, ok)
+	sources, err := provider.Discover(context.Background())
+	require.NoError(t, err)
+	require.Len(t, sources, 1)
+
+	legacyResults, legacyExcluded, err := parser.ParseClaudeSessionWithExclusions(
+		sourcePath,
+		"demo",
+		"devbox",
+	)
+	require.NoError(t, err)
+	require.Len(t, legacyResults, 1)
+
+	observation, err := ObserveProviderSource(context.Background(), provider, ProviderObserveRequest{
+		Source:  sources[0],
+		Machine: "devbox",
+	})
+	require.NoError(t, err)
+	require.Len(t, observation.Results, 1)
+	legacyResults[0].Session.File.Hash = observation.Fingerprint.Hash
+
+	assert.Equal(t, legacyResults[0].Session, observation.Results[0].Session)
+	assert.Equal(t, legacyResults[0].Messages, observation.Results[0].Messages)
+	assert.Equal(t, legacyResults[0].UsageEvents, observation.Results[0].UsageEvents)
+	assert.Equal(t, legacyExcluded, observation.ExcludedSessionIDs)
+	assert.Equal(t, []string{legacyResults[0].Session.ID}, observation.Planned.DataVersionSessionIDs())
+	assert.Empty(t, observation.Planned.Diagnostics)
+}
+
+func claudeShadowFixture() string {
+	return testjsonl.JoinJSONL(
+		testjsonl.ClaudeUserJSON("provider question", "2026-01-02T03:04:05Z"),
+		testjsonl.ClaudeAssistantJSON("Done.", "2026-01-02T03:04:06Z"),
+	)
+}