Migrate db, auth, and config to mcdsl

- db.Open: delegate to mcdsl/db.Open
- db.Migrate: rewrite migrations as mcdsl/db.Migration SQL strings,
  delegate to mcdsl/db.Migrate; keep SchemaVersion via mcdsl
- auth: thin shim wrapping mcdsl/auth.Authenticator, keeps Claims
  type (with Subject, AccountType, Roles) for policy engine compat;
  delete cache.go (handled by mcdsl/auth); add ErrForbidden
- config: embed mcdsl/config.Base for standard sections (Server with
  Duration fields, Database, MCIAS, Log); keep StorageConfig and
  WebConfig as MCR-specific; use mcdsl/config.Load[T] + Validator
- WriteTimeout now defaults to 30s (mcdsl default, was 0)
- All existing tests pass (auth tests rewritten for new shim API,
  cache expiry test removed — caching tested in mcdsl)
- Net -464 lines

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

go.mod

@@ -2,25 +2,31 @@ module git.wntrmute.dev/kyle/mcr
 
 go 1.25.7
 
+require (
+	git.wntrmute.dev/kyle/mcdsl v0.0.0
+	github.com/go-chi/chi/v5 v5.2.5
+	github.com/google/uuid v1.6.0
+	github.com/spf13/cobra v1.10.2
+	google.golang.org/grpc v1.79.3
+)
+
 require (
 	github.com/dustin/go-humanize v1.0.1 // indirect
-	github.com/go-chi/chi/v5 v5.2.5 // indirect
-	github.com/google/uuid v1.6.0 // indirect
 	github.com/inconshreveable/mousetrap v1.1.0 // indirect
 	github.com/mattn/go-isatty v0.0.20 // indirect
 	github.com/ncruces/go-strftime v1.0.0 // indirect
-	github.com/pelletier/go-toml/v2 v2.2.4 // indirect
+	github.com/pelletier/go-toml/v2 v2.3.0 // indirect
 	github.com/remyoudompheng/bigfft v0.0.0-20230129092748-24d4a6f8daec // indirect
-	github.com/spf13/cobra v1.10.2 // indirect
 	github.com/spf13/pflag v1.0.9 // indirect
 	golang.org/x/net v0.48.0 // indirect
 	golang.org/x/sys v0.42.0 // indirect
 	golang.org/x/text v0.32.0 // indirect
 	google.golang.org/genproto/googleapis/rpc v0.0.0-20251202230838-ff82c1b0f217 // indirect
-	google.golang.org/grpc v1.79.3 // indirect
 	google.golang.org/protobuf v1.36.11 // indirect
 	modernc.org/libc v1.70.0 // indirect
 	modernc.org/mathutil v1.7.1 // indirect
 	modernc.org/memory v1.11.0 // indirect
 	modernc.org/sqlite v1.47.0 // indirect
 )
+
+replace git.wntrmute.dev/kyle/mcdsl => /home/kyle/src/metacircular/mcdsl