feat(activity): add --by-activity flag to break down spent time by activity type

- Load time entry activity names from Redmine enumeration.
- Aggregate hours per issue and per activity in fetch_issues_with_spent_time.
- Add --by-activity CLI flag and propagate it through report builder,
  summary, and all formatters (console, CSV, HTML, JSON, ODT).
- Keep backward-compatible 2-tuple input in build_grouped_report.
- Bump version to 1.8.0.

Closes #41

redmine_reporter/cli.py

@@ -88,6 +88,11 @@ def main(argv: Optional[List[str]] = None) -> int:
         "--user-name",
         help="Redmine user full name for the report (alternative to --user-id; ambiguous names are rejected)",
     )
+    parser.add_argument(
+        "--by-activity",
+        action="store_true",
+        help="Break down spent time by activity type",
+    )
     args = parser.parse_args(argv)
 
     # Валидация взаимоисключающих флагов пользователя
@@ -130,6 +135,7 @@ def main(argv: Optional[List[str]] = None) -> int:
             from_date,
             to_date,
             user_id=args.user_id or args.user_login or args.user_name,
+            by_activity=args.by_activity,
         )
     except RedmineAPIError as e:
         print(f"❌ {e.message}", file=sys.stderr)
@@ -150,15 +156,25 @@ def main(argv: Optional[List[str]] = None) -> int:
 
     print(f"✅ Total issues: {len(issue_hours)} [{args.date}]", file=sys.stderr)
 
-    rows = build_grouped_report(issue_hours, fill_time=not args.no_time)
+    rows = build_grouped_report(
+        issue_hours,
+        fill_time=not args.no_time,
+        by_activity=args.by_activity,
+    )
 
     if args.summary:
-        summary = calculate_summary(rows)
+        summary = calculate_summary(rows, by_activity=args.by_activity)
         print(f"⏱️  Total time: {summary['total']}h", file=sys.stderr)
-        for key, value in summary.items():
+        project_keys = [k for k in sorted(summary) if k.startswith("project:")]
+        activity_keys = [k for k in sorted(summary) if k.startswith("activity:")]
+        for key in project_keys + activity_keys:
+            value = summary[key]
             if key.startswith("project:"):
                 project = key.split(":", 1)[1]
                 print(f"   {project}: {value}h", file=sys.stderr)
+            elif key.startswith("activity:"):
+                activity = key.split(":", 1)[1]
+                print(f"   [{activity}]: {value}h", file=sys.stderr)
 
     if args.output:
         output_ext = os.path.splitext(args.output)[1].lower()