A stopped tool drops its membership handler and a stopped bundle starts no copy on a call, so a replaced bundle's old tools stay gone (issue 1945, review round 2)

Its events are refused before the old bundle stops, the bundle watch follows a directory made between
its stat and its watch, and a bundle's reason is read without node's colour codes.

node-tools/internal/launch/launch.go

@@ -174,6 +174,11 @@ func (c *child) write(m any) error {
 
 var stackLine = regexp.MustCompile(`^\s+at\s`)
 
+// colour is a terminal's colour or style sequence, which node writes into a stack trace when its
+// environment asks for colour (FORCE_COLOR): taken out before a line is judged or kept as a bundle's
+// reason, so the reason reads the same in every environment.
+var colour = regexp.MustCompile("\x1b\\[[0-9;]*m")
+
 // Start launches one bundle and learns its tools. It fails when the child cannot be started or does
 // not complete the handshake. A child that exits later is started again on its next call.
 func Start(module, entry string, env []string, mesh Bus, logf func(string, ...any)) (*Launched, error) {
@@ -245,9 +250,10 @@ func Start(module, entry string, env []string, mesh Bus, logf func(string, ...an
 					continue
 				}
 				logf("[%s] %s", module, line)
-				if !stackLine.MatchString(line) && !strings.HasPrefix(line, "Node.js v") {
+				plain := colour.ReplaceAllString(line, "")
+				if !stackLine.MatchString(plain) && !strings.HasPrefix(plain, "Node.js v") {
 					saidMu.Lock()
-					lastSaid = strings.TrimSpace(line)
+					lastSaid = strings.TrimSpace(plain)
 					saidMu.Unlock()
 				}
 			}
@@ -456,14 +462,24 @@ func Start(module, entry string, env []string, mesh Bus, logf func(string, ...an
 
 	asking := func(method string, params any, timeout time.Duration) (json.RawMessage, error) {
 		mu.Lock()
-		c := current
+		c, gone := current, stopped
 		mu.Unlock()
+		if gone {
+			// A stopped bundle is never started again by a call: a process started now would be one
+			// nothing stops (issue 1945).
+			return nil, fmt.Errorf("%s's bundle is stopped; it answers no call", module)
+		}
 		if c == nil {
 			fresh, err := start()
 			if err != nil {
 				return nil, err
 			}
 			mu.Lock()
+			if stopped {
+				mu.Unlock()
+				_ = fresh.cmd.Process.Signal(syscall.SIGTERM)
+				return nil, fmt.Errorf("%s's bundle is stopped; it answers no call", module)
+			}
 			if current == nil {
 				current = fresh
 				startedAt = time.Now()