feat(config): add GetSyncMode, GetConflictStrategy, GetSovereignty with warnings

Add config accessor functions for sync mode, conflict strategy, and
federation sovereignty tier settings. These functions:

- Read from config.yaml via viper
- Validate against known valid values
- Return sensible defaults when not set
- Log warnings to stderr when invalid values are configured (instead
  of silently falling back to defaults)

Closes: hq-ew1mbr.26

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

internal/config/sync.go

@@ -0,0 +1,140 @@
+package config
+
+import (
+	"fmt"
+	"os"
+	"strings"
+)
+
+// Sync mode configuration values (from hq-ew1mbr.3)
+// These control how Dolt syncs with JSONL/remotes.
+
+// SyncMode represents the sync mode configuration
+type SyncMode string
+
+const (
+	// SyncModeGitPortable exports JSONL on push, imports on pull (default)
+	SyncModeGitPortable SyncMode = "git-portable"
+	// SyncModeRealtime exports JSONL on every change (legacy behavior)
+	SyncModeRealtime SyncMode = "realtime"
+	// SyncModeDoltNative uses Dolt remote directly (dolthub://, gs://, s3://)
+	SyncModeDoltNative SyncMode = "dolt-native"
+	// SyncModeBeltAndSuspenders uses Dolt remote + JSONL backup
+	SyncModeBeltAndSuspenders SyncMode = "belt-and-suspenders"
+)
+
+// validSyncModes is the set of allowed sync mode values
+var validSyncModes = map[SyncMode]bool{
+	SyncModeGitPortable:       true,
+	SyncModeRealtime:          true,
+	SyncModeDoltNative:        true,
+	SyncModeBeltAndSuspenders: true,
+}
+
+// ConflictStrategy represents the conflict resolution strategy
+type ConflictStrategy string
+
+const (
+	// ConflictStrategyNewest uses last-write-wins (default)
+	ConflictStrategyNewest ConflictStrategy = "newest"
+	// ConflictStrategyOurs prefers local changes
+	ConflictStrategyOurs ConflictStrategy = "ours"
+	// ConflictStrategyTheirs prefers remote changes
+	ConflictStrategyTheirs ConflictStrategy = "theirs"
+	// ConflictStrategyManual requires manual resolution
+	ConflictStrategyManual ConflictStrategy = "manual"
+)
+
+// validConflictStrategies is the set of allowed conflict strategy values
+var validConflictStrategies = map[ConflictStrategy]bool{
+	ConflictStrategyNewest: true,
+	ConflictStrategyOurs:   true,
+	ConflictStrategyTheirs: true,
+	ConflictStrategyManual: true,
+}
+
+// Sovereignty represents the federation sovereignty tier
+type Sovereignty string
+
+const (
+	// SovereigntyT1 is the most open tier (public repos)
+	SovereigntyT1 Sovereignty = "T1"
+	// SovereigntyT2 is organization-level
+	SovereigntyT2 Sovereignty = "T2"
+	// SovereigntyT3 is pseudonymous
+	SovereigntyT3 Sovereignty = "T3"
+	// SovereigntyT4 is anonymous
+	SovereigntyT4 Sovereignty = "T4"
+)
+
+// validSovereigntyTiers is the set of allowed sovereignty values
+var validSovereigntyTiers = map[Sovereignty]bool{
+	SovereigntyT1: true,
+	SovereigntyT2: true,
+	SovereigntyT3: true,
+	SovereigntyT4: true,
+}
+
+// GetSyncMode retrieves the sync mode configuration.
+// Returns the configured mode, or SyncModeGitPortable (default) if not set or invalid.
+// Logs a warning to stderr if an invalid value is configured.
+//
+// Config key: sync.mode
+// Valid values: git-portable, realtime, dolt-native, belt-and-suspenders
+func GetSyncMode() SyncMode {
+	value := GetString("sync.mode")
+	if value == "" {
+		return SyncModeGitPortable // Default
+	}
+
+	mode := SyncMode(strings.ToLower(strings.TrimSpace(value)))
+	if !validSyncModes[mode] {
+		fmt.Fprintf(os.Stderr, "Warning: invalid sync.mode %q in config (valid: git-portable, realtime, dolt-native, belt-and-suspenders), using default 'git-portable'\n", value)
+		return SyncModeGitPortable
+	}
+
+	return mode
+}
+
+// GetConflictStrategy retrieves the conflict resolution strategy configuration.
+// Returns the configured strategy, or ConflictStrategyNewest (default) if not set or invalid.
+// Logs a warning to stderr if an invalid value is configured.
+//
+// Config key: conflict.strategy
+// Valid values: newest, ours, theirs, manual
+func GetConflictStrategy() ConflictStrategy {
+	value := GetString("conflict.strategy")
+	if value == "" {
+		return ConflictStrategyNewest // Default
+	}
+
+	strategy := ConflictStrategy(strings.ToLower(strings.TrimSpace(value)))
+	if !validConflictStrategies[strategy] {
+		fmt.Fprintf(os.Stderr, "Warning: invalid conflict.strategy %q in config (valid: newest, ours, theirs, manual), using default 'newest'\n", value)
+		return ConflictStrategyNewest
+	}
+
+	return strategy
+}
+
+// GetSovereignty retrieves the federation sovereignty tier configuration.
+// Returns the configured tier, or SovereigntyT1 (default) if not set or invalid.
+// Logs a warning to stderr if an invalid value is configured.
+//
+// Config key: federation.sovereignty
+// Valid values: T1, T2, T3, T4
+func GetSovereignty() Sovereignty {
+	value := GetString("federation.sovereignty")
+	if value == "" {
+		return SovereigntyT1 // Default
+	}
+
+	// Normalize to uppercase for comparison (T1, T2, etc.)
+	tier := Sovereignty(strings.ToUpper(strings.TrimSpace(value)))
+	if !validSovereigntyTiers[tier] {
+		fmt.Fprintf(os.Stderr, "Warning: invalid federation.sovereignty %q in config (valid: T1, T2, T3, T4), using default 'T1'\n", value)
+		return SovereigntyT1
+	}
+
+	return tier
+}

internal/config/sync_test.go

@@ -0,0 +1,329 @@
+package config
+
+import (
+	"bytes"
+	"os"
+	"strings"
+	"testing"
+)
+
+func TestGetSyncMode(t *testing.T) {
+	tests := []struct {
+		name           string
+		configValue    string
+		expectedMode   SyncMode
+		expectsWarning bool
+	}{
+		{
+			name:           "empty returns default",
+			configValue:    "",
+			expectedMode:   SyncModeGitPortable,
+			expectsWarning: false,
+		},
+		{
+			name:           "git-portable is valid",
+			configValue:    "git-portable",
+			expectedMode:   SyncModeGitPortable,
+			expectsWarning: false,
+		},
+		{
+			name:           "realtime is valid",
+			configValue:    "realtime",
+			expectedMode:   SyncModeRealtime,
+			expectsWarning: false,
+		},
+		{
+			name:           "dolt-native is valid",
+			configValue:    "dolt-native",
+			expectedMode:   SyncModeDoltNative,
+			expectsWarning: false,
+		},
+		{
+			name:           "belt-and-suspenders is valid",
+			configValue:    "belt-and-suspenders",
+			expectedMode:   SyncModeBeltAndSuspenders,
+			expectsWarning: false,
+		},
+		{
+			name:           "mixed case is normalized",
+			configValue:    "Git-Portable",
+			expectedMode:   SyncModeGitPortable,
+			expectsWarning: false,
+		},
+		{
+			name:           "whitespace is trimmed",
+			configValue:    "  realtime  ",
+			expectedMode:   SyncModeRealtime,
+			expectsWarning: false,
+		},
+		{
+			name:           "invalid value returns default with warning",
+			configValue:    "invalid-mode",
+			expectedMode:   SyncModeGitPortable,
+			expectsWarning: true,
+		},
+		{
+			name:           "typo returns default with warning",
+			configValue:    "git-portabel",
+			expectedMode:   SyncModeGitPortable,
+			expectsWarning: true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			// Reset viper for test
+			ResetForTesting()
+			if err := Initialize(); err != nil {
+				t.Fatalf("Initialize failed: %v", err)
+			}
+
+			// Set the config value
+			if tt.configValue != "" {
+				Set("sync.mode", tt.configValue)
+			}
+
+			// Capture stderr
+			oldStderr := os.Stderr
+			r, w, _ := os.Pipe()
+			os.Stderr = w
+
+			result := GetSyncMode()
+
+			// Restore stderr and get output
+			w.Close()
+			os.Stderr = oldStderr
+			var buf bytes.Buffer
+			buf.ReadFrom(r)
+			stderrOutput := buf.String()
+
+			if result != tt.expectedMode {
+				t.Errorf("GetSyncMode() = %q, want %q", result, tt.expectedMode)
+			}
+
+			hasWarning := strings.Contains(stderrOutput, "Warning:")
+			if tt.expectsWarning && !hasWarning {
+				t.Errorf("Expected warning in stderr, got none. stderr=%q", stderrOutput)
+			}
+			if !tt.expectsWarning && hasWarning {
+				t.Errorf("Unexpected warning in stderr: %q", stderrOutput)
+			}
+		})
+	}
+}
+
+func TestGetConflictStrategy(t *testing.T) {
+	tests := []struct {
+		name             string
+		configValue      string
+		expectedStrategy ConflictStrategy
+		expectsWarning   bool
+	}{
+		{
+			name:             "empty returns default",
+			configValue:      "",
+			expectedStrategy: ConflictStrategyNewest,
+			expectsWarning:   false,
+		},
+		{
+			name:             "newest is valid",
+			configValue:      "newest",
+			expectedStrategy: ConflictStrategyNewest,
+			expectsWarning:   false,
+		},
+		{
+			name:             "ours is valid",
+			configValue:      "ours",
+			expectedStrategy: ConflictStrategyOurs,
+			expectsWarning:   false,
+		},
+		{
+			name:             "theirs is valid",
+			configValue:      "theirs",
+			expectedStrategy: ConflictStrategyTheirs,
+			expectsWarning:   false,
+		},
+		{
+			name:             "manual is valid",
+			configValue:      "manual",
+			expectedStrategy: ConflictStrategyManual,
+			expectsWarning:   false,
+		},
+		{
+			name:             "mixed case is normalized",
+			configValue:      "NEWEST",
+			expectedStrategy: ConflictStrategyNewest,
+			expectsWarning:   false,
+		},
+		{
+			name:             "whitespace is trimmed",
+			configValue:      "  ours  ",
+			expectedStrategy: ConflictStrategyOurs,
+			expectsWarning:   false,
+		},
+		{
+			name:             "invalid value returns default with warning",
+			configValue:      "invalid-strategy",
+			expectedStrategy: ConflictStrategyNewest,
+			expectsWarning:   true,
+		},
+		{
+			name:             "last-write-wins typo returns default with warning",
+			configValue:      "last-write-wins",
+			expectedStrategy: ConflictStrategyNewest,
+			expectsWarning:   true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			// Reset viper for test
+			ResetForTesting()
+			if err := Initialize(); err != nil {
+				t.Fatalf("Initialize failed: %v", err)
+			}
+
+			// Set the config value
+			if tt.configValue != "" {
+				Set("conflict.strategy", tt.configValue)
+			}
+
+			// Capture stderr
+			oldStderr := os.Stderr
+			r, w, _ := os.Pipe()
+			os.Stderr = w
+
+			result := GetConflictStrategy()
+
+			// Restore stderr and get output
+			w.Close()
+			os.Stderr = oldStderr
+			var buf bytes.Buffer
+			buf.ReadFrom(r)
+			stderrOutput := buf.String()
+
+			if result != tt.expectedStrategy {
+				t.Errorf("GetConflictStrategy() = %q, want %q", result, tt.expectedStrategy)
+			}
+
+			hasWarning := strings.Contains(stderrOutput, "Warning:")
+			if tt.expectsWarning && !hasWarning {
+				t.Errorf("Expected warning in stderr, got none. stderr=%q", stderrOutput)
+			}
+			if !tt.expectsWarning && hasWarning {
+				t.Errorf("Unexpected warning in stderr: %q", stderrOutput)
+			}
+		})
+	}
+}
+
+func TestGetSovereignty(t *testing.T) {
+	tests := []struct {
+		name           string
+		configValue    string
+		expectedTier   Sovereignty
+		expectsWarning bool
+	}{
+		{
+			name:           "empty returns default",
+			configValue:    "",
+			expectedTier:   SovereigntyT1,
+			expectsWarning: false,
+		},
+		{
+			name:           "T1 is valid",
+			configValue:    "T1",
+			expectedTier:   SovereigntyT1,
+			expectsWarning: false,
+		},
+		{
+			name:           "T2 is valid",
+			configValue:    "T2",
+			expectedTier:   SovereigntyT2,
+			expectsWarning: false,
+		},
+		{
+			name:           "T3 is valid",
+			configValue:    "T3",
+			expectedTier:   SovereigntyT3,
+			expectsWarning: false,
+		},
+		{
+			name:           "T4 is valid",
+			configValue:    "T4",
+			expectedTier:   SovereigntyT4,
+			expectsWarning: false,
+		},
+		{
+			name:           "lowercase is normalized",
+			configValue:    "t1",
+			expectedTier:   SovereigntyT1,
+			expectsWarning: false,
+		},
+		{
+			name:           "whitespace is trimmed",
+			configValue:    "  T2  ",
+			expectedTier:   SovereigntyT2,
+			expectsWarning: false,
+		},
+		{
+			name:           "invalid value returns default with warning",
+			configValue:    "T5",
+			expectedTier:   SovereigntyT1,
+			expectsWarning: true,
+		},
+		{
+			name:           "invalid tier 0 returns default with warning",
+			configValue:    "T0",
+			expectedTier:   SovereigntyT1,
+			expectsWarning: true,
+		},
+		{
+			name:           "word tier returns default with warning",
+			configValue:    "public",
+			expectedTier:   SovereigntyT1,
+			expectsWarning: true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			// Reset viper for test
+			ResetForTesting()
+			if err := Initialize(); err != nil {
+				t.Fatalf("Initialize failed: %v", err)
+			}
+
+			// Set the config value
+			if tt.configValue != "" {
+				Set("federation.sovereignty", tt.configValue)
+			}
+
+			// Capture stderr
+			oldStderr := os.Stderr
+			r, w, _ := os.Pipe()
+			os.Stderr = w
+
+			result := GetSovereignty()
+
+			// Restore stderr and get output
+			w.Close()
+			os.Stderr = oldStderr
+			var buf bytes.Buffer
+			buf.ReadFrom(r)
+			stderrOutput := buf.String()
+
+			if result != tt.expectedTier {
+				t.Errorf("GetSovereignty() = %q, want %q", result, tt.expectedTier)
+			}
+
+			hasWarning := strings.Contains(stderrOutput, "Warning:")
+			if tt.expectsWarning && !hasWarning {
+				t.Errorf("Expected warning in stderr, got none. stderr=%q", stderrOutput)
+			}
+			if !tt.expectsWarning && hasWarning {
+				t.Errorf("Unexpected warning in stderr: %q", stderrOutput)
+			}
+		})
+	}
+}