test(02-02): add failing tests for PPID chain walk + workspace resolution

- TestReadPPID, TestReadPPIDMissing
- TestResolveWorkspace, TestResolveWorkspaceNotFound, TestResolveWorkspaceMaxDepth
- TestBuildTerminalWorkspaceMapUnit
- Add go.i3wm.org/i3/v4 dependency

workspace.go

@@ -0,0 +1,32 @@
+package main
+
+import (
+	i3 "go.i3wm.org/i3/v4"
+)
+
+// X11PIDResolver abstrait la lecture de _NET_WM_PID pour testabilite.
+type X11PIDResolver interface {
+	GetPID(windowID int64) (int, error)
+}
+
+// I3TreeProvider abstrait i3.GetTree() pour testabilite.
+type I3TreeProvider interface {
+	GetTree() (i3.Tree, error)
+}
+
+// ReadPPID lit le PPid depuis /proc/PID/status. procDir injectable pour les tests.
+func ReadPPID(procDir string, pid int) (int, error) {
+	return 0, nil
+}
+
+// ResolveWorkspace remonte la chaine PPID depuis claudePID jusqu'a trouver
+// un PID connu dans terminalWorkspaces. Max 20 niveaux.
+func ResolveWorkspace(procDir string, claudePID int, terminalWorkspaces map[int]string) string {
+	return ""
+}
+
+// BuildTerminalWorkspaceMap construit la map terminalPID -> workspaceName.
+// Utilise i3 GetTree + X11 _NET_WM_PID.
+func BuildTerminalWorkspaceMap(tree I3TreeProvider, x11 X11PIDResolver) (map[int]string, error) {
+	return nil, nil
+}