feat(v0.5.3): summary fields for end_reason / ownership / adoption

internal/session/summary.go

@@ -26,6 +26,25 @@ type SessionSummary struct {
 	FilesModified   []string  `json:"files_modified"`
 	FilesDeleted    []string  `json:"files_deleted"`
 	NotesUpdated    bool      `json:"notes_updated"`
+
+	// EndReason is "child_exited" for direct mode, "tmux_session_ended" for
+	// persistent mode (both owner-create and adopted reattach). Optional;
+	// pre-v0.5.3 summaries omit it.
+	EndReason string `json:"end_reason,omitempty"`
+
+	// DetectedVia distinguishes the mechanism that observed session end:
+	// "child_exit" for direct mode, "polling" for persistent mode.
+	DetectedVia string `json:"detected_via,omitempty"`
+
+	// SessionOwnership is "created" if this ctask process originated the
+	// session (owner-create) or "adopted" if it took over an orphaned
+	// persistent session. Omitted in direct mode.
+	SessionOwnership string `json:"session_ownership,omitempty"`
+
+	// AdoptedFromOrphanAt records the moment adoption took place. Set only
+	// for adopted reattach.
+	AdoptedFromOrphanAt *time.Time `json:"adopted_from_orphan_at,omitempty"`
+
 	// EndManifest captures the workspace file list at end-of-session so the
 	// next session can diff current state against it (Layer 3). This field
 	// is ctask-internal; it is not part of the public summary format shown