docs, comments: the drift the audit listed (audit 2026-10-17, stage 6)

The lines under "Doc and comment drift" that the findings' own commits
did not already fix:
- security.md: a newer confirmation link replaces the older, a reset link
  is not replaced; html/template renders every page (no themes); the
  container keeps eight capabilities, named, not "KILL".
- architecture.md: ImportKey writes over a name's key, as an import must;
  the error text reaches the browser on the Backup page's import refusal.
- guide: with Caddy the key is in Caddy's data, so a full backup refuses
  until certs/ holds a copy (or back up caddy-data).
- comments: sasldb2 holds application passwords in the clear (store,
  app/password.go); texthash folds ASCII (sender.go); the supervisor
  socket's group is supervisor (rpc.go); cert-reload's OpenSSL measurement
  was 3.0.x of bookworm; sendReset's limits (links.go).
Migration 0013's comment stays as shipped.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

internal/store/applications.go

@@ -29,8 +29,8 @@ const (
 
 // Application is a SASL account bound to a single domain (product.md §
 // Multi-domain model). The password is never stored here — only in sasldb2,
-// hashed — so it can be shown exactly once at creation/regeneration
-// (security.md). Addresses is populated only in 'list' mode.
+// which Cyrus keeps in the clear (PLAIN and LOGIN need it; security.md) — so
+// it can be shown exactly once at creation/regeneration. Addresses is populated only in 'list' mode.
 type Application struct {
 	ID             int64
 	DomainID       int64