feat(tui): add process features watch and kill

internal/tui/messages.go

@@ -1,7 +1,9 @@
 package tui
 
 import (
+	"fmt"
 	"snitch/internal/collector"
+	"syscall"
 	"time"
 
 	tea "github.com/charmbracelet/bubbletea"
@@ -17,6 +19,15 @@ type errMsg struct {
 	err error
 }
 
+type killResultMsg struct {
+	pid     int
+	process string
+	success bool
+	err     error
+}
+
+type clearStatusMsg struct{}
+
 func (m model) tick() tea.Cmd {
 	return tea.Tick(m.interval, func(t time.Time) tea.Msg {
 		return tickMsg(t)
@@ -33,3 +44,40 @@ func (m model) fetchData() tea.Cmd {
 	}
 }
 
+func killProcess(pid int, process string) tea.Cmd {
+	return func() tea.Msg {
+		if pid <= 0 {
+			return killResultMsg{
+				pid:     pid,
+				process: process,
+				success: false,
+				err:     fmt.Errorf("invalid pid"),
+			}
+		}
+
+		// send SIGTERM first (graceful shutdown)
+		err := syscall.Kill(pid, syscall.SIGTERM)
+		if err != nil {
+			return killResultMsg{
+				pid:     pid,
+				process: process,
+				success: false,
+				err:     err,
+			}
+		}
+
+		return killResultMsg{
+			pid:     pid,
+			process: process,
+			success: true,
+			err:     nil,
+		}
+	}
+}
+
+func clearStatusAfter(d time.Duration) tea.Cmd {
+	return tea.Tick(d, func(t time.Time) tea.Msg {
+		return clearStatusMsg{}
+	})
+}
+