Add activity logs, sidebar badges, and logout with working alert colors.

Record auth audits and surface them in Activity, poll sidebar counts without resetting idle, and add a profile logout path plus theme red/green/blue tokens so failure badges render.

service/internal/settings/auth_audit.go

@@ -0,0 +1,77 @@
+package settings
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"os"
+	"path/filepath"
+)
+
+// MaxAuthAuditEvents is the retention cap for auth-audit.json.
+const MaxAuthAuditEvents = 1000
+
+// LoadAuthAudit reads and parses auth-audit.json from dir.
+func LoadAuthAudit(dir string) (AuthAuditStore, error) {
+	path := filepath.Join(dir, AuthAuditFileName)
+	payload, err := os.ReadFile(path)
+	if err != nil {
+		return AuthAuditStore{}, err
+	}
+
+	var store AuthAuditStore
+	if err := json.Unmarshal(payload, &store); err != nil {
+		return AuthAuditStore{}, fmt.Errorf("parse auth audit: %w", err)
+	}
+	if store.Events == nil {
+		store.Events = []AuthAuditEvent{}
+	}
+	return store, nil
+}
+
+// LoadAuthAuditOrEmpty returns an empty store when auth-audit.json is missing.
+func LoadAuthAuditOrEmpty(dir string) (AuthAuditStore, error) {
+	store, err := LoadAuthAudit(dir)
+	if err != nil {
+		if errors.Is(err, os.ErrNotExist) {
+			return AuthAuditStore{Events: []AuthAuditEvent{}}, nil
+		}
+		return AuthAuditStore{}, err
+	}
+	return store, nil
+}
+
+// SaveAuthAudit writes auth-audit.json to dir with mode 0640.
+func SaveAuthAudit(dir string, store AuthAuditStore) error {
+	if err := ensureConfigDir(dir); err != nil {
+		return err
+	}
+	if store.Events == nil {
+		store.Events = []AuthAuditEvent{}
+	}
+
+	payload, err := json.MarshalIndent(store, "", "  ")
+	if err != nil {
+		return fmt.Errorf("encode auth audit: %w", err)
+	}
+	payload = append(payload, '\n')
+
+	path := filepath.Join(dir, AuthAuditFileName)
+	if err := os.WriteFile(path, payload, 0o640); err != nil {
+		return fmt.Errorf("write auth audit: %w", err)
+	}
+	return nil
+}
+
+// AppendAuthAuditEvent appends event and trims to MaxAuthAuditEvents (newest kept).
+func AppendAuthAuditEvent(dir string, event AuthAuditEvent) error {
+	store, err := LoadAuthAuditOrEmpty(dir)
+	if err != nil {
+		return err
+	}
+	store.Events = append(store.Events, event)
+	if len(store.Events) > MaxAuthAuditEvents {
+		store.Events = store.Events[len(store.Events)-MaxAuthAuditEvents:]
+	}
+	return SaveAuthAudit(dir, store)
+}