feat: auth hardening + codebase quality sweep

Refresh tokens: RefreshToken entity, PostgresRefreshTokenRepository,
login returns refresh token, POST /auth/refresh (rotation), POST /auth/logout,
JWT expiry 24h→1h, configurable via with_expiry().

Route protection: require_auth middleware on protected routes,
public routes split (register, login, refresh, sharing/access).

Authorization: caller_id added to ReadAssetFileQuery, ReadDerivativeQuery,
GetStackQuery, DeleteStackCommand with ownership checks. Admin-only gates
on processing, storage, sidecar, duplicates handlers.

Quality fixes: visibility filtering bypass in search(), unwrap panics in
date parsing, DRY auth header parsing, centralized parsers module,
email validation via email_address crate, value objects (Username, MimeType,
RelativePath), domain events (UserCreated, UserDeleted, AlbumCreated,
TagCreated, DuplicateDetected), postgres error mapping for constraint
violations, OptionExt::or_not_found helper, in_memory_repo! macro,
GetStackQuery moved to queries, album add_entry 200→201.

Cargo.lock

@@ -815,6 +815,7 @@ dependencies = [
  "async-trait",
  "bytes",
  "chrono",
+ "email_address",
  "futures",
  "serde",
  "serde_json",
@@ -859,6 +860,15 @@ dependencies = [
  "serde",
 ]
 
+[[package]]
+name = "email_address"
+version = "0.2.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e079f19b08ca6239f47f8ba8509c11cf3ea30095831f7fed61441475edd8c449"
+dependencies = [
+ "serde",
+]
+
 [[package]]
 name = "encoding_rs"
 version = "0.8.35"
@@ -894,6 +904,16 @@ version = "1.0.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "877a4ace8713b0bcf2a4e7eec82529c029f1d0619886d18145fea96c3ffe5c0f"
 
+[[package]]
+name = "errno"
+version = "0.3.14"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "39cab71617ae0d63f51a36d69f866391735b51691dbda63cf6f96d042b63efeb"
+dependencies = [
+ "libc",
+ "windows-sys 0.61.2",
+]
+
 [[package]]
 name = "etcetera"
 version = "0.8.0"
@@ -2979,6 +2999,16 @@ version = "1.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0fda2ff0d084019ba4d7c6f371c95d8fd75ce3524c3cb8fb653a3023f6323e64"
 
+[[package]]
+name = "signal-hook-registry"
+version = "1.4.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c4db69cba1110affc0e9f7bcd48bbf87b3f4fc7c61fc9155afd4c469eb3d6c1b"
+dependencies = [
+ "errno",
+ "libc",
+]
+
 [[package]]
 name = "signatory"
 version = "0.27.1"
@@ -3452,6 +3482,7 @@ dependencies = [
  "libc",
  "mio",
  "pin-project-lite",
+ "signal-hook-registry",
  "socket2",
  "tokio-macros",
  "windows-sys 0.61.2",