feat(accounts): outgoing mail over SMTP (Resend), email verification, fail-closed password reset

- mail/ module (lettre, ru/en templates), links built only from PUBLIC_BASE_URL
- migration 0006: accounts.email_verified_at, shared email_tokens table (verify + reset), existing accounts marked verified
- reset mailer no longer logs tokens; RESET_MAIL_MODE=log is dev-only and refused with COOKIE_SECURE=true; Disabled by default answers 503
- forgot-password and resend-verification do their work in a background task (no timing oracle)
- device linking requires a verified email; email_verified exposed via /me and gRPC
- gateway rate limits, SMTP_* in compose and .env.example
- frontend: verify, forgot-password, reset-password pages, verify banner, ru/en strings

backend/Cargo.lock

@@ -20,6 +20,7 @@ dependencies = [
  "dotenvy",
  "hex",
  "image",
+ "lettre",
  "rand 0.10.3",
  "serde",
  "serde_json",
@@ -1291,6 +1292,16 @@ dependencies = [
  "zeroize",
 ]
 
+[[package]]
+name = "email-encoding"
+version = "0.4.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "420b9da095f052ea597503e39073b5b3c522f7db933fbac202d91d24492693fd"
+dependencies = [
+ "base64 0.23.1",
+ "memchr",
+]
+
 [[package]]
 name = "email_address"
 version = "0.2.9"
@@ -2274,6 +2285,33 @@ dependencies = [
  "spin 0.9.9",
 ]
 
+[[package]]
+name = "lettre"
+version = "0.11.23"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f2c646bd5cc763b1087b15493e29a64be6147ba8f19342004fa52048ee596eae"
+dependencies = [
+ "async-trait",
+ "base64 0.23.1",
+ "email-encoding",
+ "email_address",
+ "fastrand",
+ "futures-io",
+ "futures-util",
+ "httpdate",
+ "idna",
+ "mime",
+ "nom",
+ "percent-encoding",
+ "quoted_printable",
+ "rustls 0.23.45",
+ "socket2 0.6.5",
+ "tokio",
+ "tokio-rustls 0.26.5",
+ "url",
+ "webpki-roots",
+]
+
 [[package]]
 name = "libc"
 version = "0.2.189"
@@ -2470,6 +2508,15 @@ version = "1.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "743fb55ba31b18fb1ecef6bdc9aa2743314978ac084044301a7eee33fb99a20d"
 
+[[package]]
+name = "nom"
+version = "8.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "df9761775871bdef83bee530e60050f7e54b1105350d6884eb0fb4f46c2f9405"
+dependencies = [
+ "memchr",
+]
+
 [[package]]
 name = "nonzero_ext"
 version = "0.3.0"
@@ -2947,6 +2994,12 @@ dependencies = [
  "proc-macro2",
 ]
 
+[[package]]
+name = "quoted_printable"
+version = "0.5.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "478e0585659a122aa407eb7e3c0e1fa51b1d8a870038bd29f0cf4a8551eea972"
+
 [[package]]
 name = "r-efi"
 version = "5.3.0"
@@ -3229,6 +3282,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0d41d731c7d2f962d1ccc364cec258de3c0e93b38c2fb3ba97ac74513048d634"
 dependencies = [
  "aws-lc-rs",
+ "log",
  "once_cell",
  "ring",
  "rustls-pki-types",