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/web/controller/login_limiter_test.go

@@ -2,13 +2,11 @@ package controller
 
 import (
 	"strconv"
+	"strings"
 	"testing"
 	"time"
 )
 
-// An unauthenticated attacker can flood /login with fresh usernames, each of
-// which seeds a record keyed on that username. The attempts map must stay
-// bounded rather than growing until the process OOMs.
 func TestLoginLimiterBoundsMemoryUnderUsernameFlood(t *testing.T) {
 	limiter := newLoginLimiter(5, 5*time.Minute, 15*time.Minute)
 	for i := 0; i < loginLimitMaxRecords+100; i++ {
@@ -24,6 +22,35 @@ func TestLoginLimiterBoundsMemoryUnderUsernameFlood(t *testing.T) {
 	}
 }
 
+func TestLoginLimiterEvictionSparesActiveBlocks(t *testing.T) {
+	now := time.Date(2026, 5, 6, 12, 0, 0, 0, time.UTC)
+	limiter := newLoginLimiter(5, 5*time.Minute, 15*time.Minute)
+	limiter.now = func() time.Time { return now }
+
+	limiter.mu.Lock()
+	for i := 0; i < loginLimitMaxRecords-1; i++ {
+		limiter.attempts["victim-"+strconv.Itoa(i)] = &loginLimitRecord{blockedUntil: now.Add(10 * time.Minute)}
+	}
+	limiter.attempts["filler"] = &loginLimitRecord{failures: []time.Time{now}}
+	limiter.mu.Unlock()
+
+	if _, blocked := limiter.registerFailure("9.9.9.9", "newcomer"); blocked {
+		t.Fatal("the eviction-triggering failure itself should not be blocked yet")
+	}
+
+	limiter.mu.Lock()
+	defer limiter.mu.Unlock()
+	survivors := 0
+	for key, record := range limiter.attempts {
+		if strings.HasPrefix(key, "victim-") && now.Before(record.blockedUntil) {
+			survivors++
+		}
+	}
+	if survivors != loginLimitMaxRecords-1 {
+		t.Fatalf("eviction under a full map dropped an actively-blocked record: %d/%d victims survived", survivors, loginLimitMaxRecords-1)
+	}
+}
+
 func TestLoginLimiterBlocksAfterConfiguredFailures(t *testing.T) {
 	now := time.Date(2026, 5, 6, 12, 0, 0, 0, time.UTC)
 	limiter := newLoginLimiter(5, 5*time.Minute, 15*time.Minute)