Step 16.1: global worklog dashboard + conservative suggestions

- Fix date timezone: worklog.Add uses local date (was UTC)
- Conservative suggestion estimator:
  - burst detection (10min window), time spread analysis
  - 5-30 min range, 60+ only with strong evidence
  - confidence levels: low/medium/high with reason
- worklog/report.go: ReportFilter, ListReport, Summary, ExportCSV, ExportMarkdown
- Expanded WorklogDTO: date, details, approximate, billable, nodeTitle
- New bindings: CreateWorklogFull, ListWorklogReport, WorklogSummary, Export*
- New system section 'Журнал' in sidebar with badge (suggestion count)
- Global journal screen: filters (date range, includeChildren), table, summary
- Suggestions shown on Today dashboard + Journal screen + per-node worklog tab
- Suggestion cards: editable minutes, confidence display, apply/open buttons
- i18n: all new keys in ru + en

internal/core/activity/suggest.go

@@ -1,11 +1,22 @@
 package activity
 
+// Confidence level for a suggestion.
+const (
+	ConfidenceLow    = "low"
+	ConfidenceMedium = "medium"
+	ConfidenceHigh   = "high"
+)
+
 // 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"`
+	NodeID           string `json:"nodeId"`
+	NodeTitle        string `json:"nodeTitle"`
+	Summary          string `json:"summary"`
+	SuggestedMin     int    `json:"suggestedMin"`
+	EventCount       int    `json:"eventCount"`
+	NodeKind         string `json:"nodeKind"`
+	Confidence       string `json:"confidence"`
+	ConfidenceReason string `json:"confidenceReason"`
+	Hidden           bool   `json:"hidden"`
+	TimeSpreadMin    int    `json:"timeSpreadMin"` // minutes between first and last event
 }