fix: fix panics, enable the forcetypeassert lint (#1123)

An unchecked type assertion panics on input it did not expect, as a missing `tool_cache` key did in https://gitea.com/gitea/runner/pulls/1122.

Every flagged site is now handled where it can fail, or typed so it cannot: a `lock.Keyed` replaces the two `sync.Map` mutex registries, and the reporter's outputs carry an explicit sent flag. Mocks keep their assertions, a mismatch there is a setup error the panic names.

Bugs it turned up (only the first is reachable from workflows):

1. A scalar `matrix.include` or `matrix.exclude`, e.g. `include: foo` or `include: [1, 2]`, panicked the runner with `interface conversion: interface {} is string, not map[string]interface {}`. Verified against `main`, it is now a workflow error. `OnSchedule` panicked the same way on a malformed `on.schedule` entry.
1. `ExternalURL()` panicked on the nil listener after `Close()`, the port is now resolved once at startup.
1. `errors.Is(err, git.ErrShortRef)` followed by `err.(*git.Error)` panics as soon as anything wraps that error, so it is `errors.As` now.
1. An output name the server acknowledged without ever being sent one was recorded as sent forever, which silently dropped a later value for that name.

48576ab3e5 fixes one discovered issue: a matrix key holding a nested object was logged and then run as if the job had no matrix, so it now fails like an unknown `exclude` key.
Reviewed-on: https://gitea.com/gitea/runner/pulls/1123
Reviewed-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: silverwind <me@silverwind.io>

act/artifactcache/handler.go

@@ -70,6 +70,7 @@ type Handler struct {
 	storage  *Storage
 	router   *httprouter.Router
 	listener net.Listener
+	port     int
 	server   *http.Server
 	logger   logrus.FieldLogger
 
@@ -177,6 +178,12 @@ func StartHandler(dir, outboundIP string, port uint16, internalSecret string, lo
 	if err != nil {
 		return nil, err
 	}
+	addr, ok := listener.Addr().(*net.TCPAddr)
+	if !ok {
+		listener.Close()
+		return nil, fmt.Errorf("cache server listens on %T, want a TCP address", listener.Addr())
+	}
+	h.port = addr.Port
 	server := &http.Server{
 		ReadHeaderTimeout: 2 * time.Second,
 		Handler:           router,
@@ -194,9 +201,7 @@ func StartHandler(dir, outboundIP string, port uint16, internalSecret string, lo
 
 func (h *Handler) ExternalURL() string {
 	// TODO: make the external url configurable if necessary
-	return fmt.Sprintf("http://%s:%d",
-		h.outboundIP,
-		h.listener.Addr().(*net.TCPAddr).Port)
+	return fmt.Sprintf("http://%s:%d", h.outboundIP, h.port)
 }
 
 // RegisterJob makes token a valid bearer credential for cache requests from