fix: close panics and races the audit's own fixes left nearby

Second-pass review of the 54-commit self-correcting audit. Each item below
was confirmed by reading the surrounding source (and, where practical, the
pre-fix code) before being changed; regression tests are included for every
behavioral fix.

Concurrency:
- eventbus: Bus.Subscribe called wg.Add with no synchronization against a
  concurrent Bus.Stop's wg.Wait, a real "WaitGroup misuse" panic risk (e.g. a
  Telegram-bot settings save racing panel shutdown/restart). Stop now flips a
  mu-guarded `stopped` flag before waiting, and Subscribe checks it under the
  same lock, so Add and Wait can no longer race.

Security:
- login_limiter: evictForRoom's fallback eviction picked an arbitrary map
  key, including ones still under an active cooldown - an attacker flooding
  /login with fresh usernames could evict their own (or anyone's) blocked
  record and reset the lockout. The fallback now skips actively-blocked
  records, only falling back to an unconditional evict if the map is
  somehow entirely full of active blocks (preserves the hard memory cap).

Subscription-endpoint panics (reachable by any client hitting /sub):
- internal/sub/service.go: applyPathAndHostParams/Obj (ws/httpupgrade/xhttp
  with no path settings object) and the TLS alpn readers in three places
  used unchecked type assertions - exactly the bug class abab7cd0 patched
  elsewhere in the same switch statements, just not these call sites.
- internal/sub/json_service.go, clash_service.go: the externalProxy loops
  in the JSON and Clash generators used unchecked assertions on a
  legacy/admin-supplied field (missing "port", non-object entry, etc.).
- internal/sub/json_service.go: realityData's shortId/serverName selection
  could assert a non-string array element.

Other correctness:
- client_traffic.go: ResetAllTraffics (touched by 3eb214d0) still skipped
  clearing NodeClientTraffic node-sync baselines, unlike its sibling reset
  paths in the same file - a node's next sync would re-add pre-reset delta
  on top of the freshly-zeroed counter.
- inbound_traffic.go: the traffic-tick tx's Commit/Rollback errors were
  silently discarded; now logged so a backend-level commit failure (e.g. an
  aborted Postgres tx from a best-effort helper) doesn't masquerade as a
  successful tick.
- outbound_subscription.go: the new subscriptionFetchClient doc comment was
  wedged between fetchAndStore's existing comment and fetchAndStore itself,
  leaving fetchAndStore undocumented and the comment describing the wrong
  function.

Convention cleanup:
- Removed narrative // comments added by the audit that violate this repo's
  no-inline-comment rule (mostly narrating the specific bug/fix rather than
  a lasting contract, and mostly on new Test functions, which this repo's
  existing tests never comment) - calibrated against this exact codebase's
  own pre-existing comment style so legitimate godoc-style doc comments
  were left alone.

internal/sub/service.go

@@ -993,7 +993,9 @@ func (s *SubService) genHysteriaLink(inbound *model.Inbound, email string) strin
 	alpns, _ := tlsSetting["alpn"].([]any)
 	var alpn []string
 	for _, a := range alpns {
-		alpn = append(alpn, a.(string))
+		if s, ok := a.(string); ok {
+			alpn = append(alpn, s)
+		}
 	}
 	if len(alpn) > 0 {
 		params["alpn"] = strings.Join(alpn, ",")
@@ -1180,7 +1182,7 @@ func unmarshalStreamSettings(streamSettings string) map[string]any {
 }
 
 func applyPathAndHostParams(settings map[string]any, params map[string]string) {
-	params["path"] = settings["path"].(string)
+	params["path"], _ = settings["path"].(string)
 	if host, ok := settings["host"].(string); ok && len(host) > 0 {
 		params["host"] = host
 	} else {
@@ -1190,7 +1192,7 @@ func applyPathAndHostParams(settings map[string]any, params map[string]string) {
 }
 
 func applyPathAndHostObj(settings map[string]any, obj map[string]any) {
-	obj["path"] = settings["path"].(string)
+	obj["path"], _ = settings["path"].(string)
 	if host, ok := settings["host"].(string); ok && len(host) > 0 {
 		obj["host"] = host
 	} else {
@@ -1312,7 +1314,9 @@ func applyShareTLSParams(stream map[string]any, params map[string]string) {
 	alpns, _ := tlsSetting["alpn"].([]any)
 	var alpn []string
 	for _, a := range alpns {
-		alpn = append(alpn, a.(string))
+		if s, ok := a.(string); ok {
+			alpn = append(alpn, s)
+		}
 	}
 	if len(alpn) > 0 {
 		params["alpn"] = strings.Join(alpn, ",")
@@ -1346,7 +1350,9 @@ func applyVmessTLSParams(stream map[string]any, obj map[string]any) {
 	if len(alpns) > 0 {
 		var alpn []string
 		for _, a := range alpns {
-			alpn = append(alpn, a.(string))
+			if s, ok := a.(string); ok {
+				alpn = append(alpn, s)
+			}
 		}
 		obj["alpn"] = strings.Join(alpn, ",")
 	}