feat: activity-based worklog suggestions (Step 16)

- Suggestion struct with nodeId, nodeTitle, summary, suggestedMin
- GetSuggestions binding: analyzes today's activity events, groups by
  node, skips nodes with existing today's worklog, generates summary
- AcceptSuggestion binding: creates worklog entry from suggestion
- HasTodayEntries helper on worklog.Service
- Suggestions panel in Worklog tab with Apply button
- i18n: worklog.suggestions / worklog.apply (ru + en)

internal/core/activity/suggest.go

@@ -0,0 +1,11 @@
+package activity
+
+// Suggestion represents a suggested worklog entry derived from today's activity.
+type Suggestion struct {
+	NodeID       string `json:"nodeId"`
+	NodeTitle    string `json:"nodeTitle"`
+	Summary      string `json:"summary"`
+	SuggestedMin int    `json:"suggestedMin"`
+	EventCount   int    `json:"eventCount"`
+	NodeKind     string `json:"nodeKind"`
+}