feat: introduce env vars validation through .env(schema, processEnv?) method

Author: tunnckoCore

README.md

@@ -1,6 +1,6 @@
 # Zagora
 
-[![ci](https://github.com/tunnckoCore/zagora/actions/workflows/ci.yml/badge.svg)](https://github.com/tunnckoCore/zagora/actions/workflows/ci.yml) <!-- COV_BADGE:START -->![coverage](https://badgen.net/badge/coverage/96.13%25/99CC09)<!-- COV_BADGE:END -->
+[![ci](https://github.com/tunnckoCore/zagora/actions/workflows/ci.yml/badge.svg)](https://github.com/tunnckoCore/zagora/actions/workflows/ci.yml) <!-- COV_BADGE:START -->![coverage](https://badgen.net/badge/coverage/95.85%25/99CC09)<!-- COV_BADGE:END -->
 
 Elevate your TypeScript workflow with Zagora: a sleek, bulletproof toolkit for forging type-safe, error-proof functions and libraries that never throw. Powered by StandardSchema-compliant validators like Zod, Valibot, and Arktype, it delivers rock-solid input/output validation and richly typed errors. No routers, no network baggage — just pure, exportable functions ready to supercharge your code. The ultimate streamlined alternative to oRPC and tRPC, stripping away the network layer for unmatched type-safety, simplicity and robustness.
 
@@ -15,7 +15,7 @@ Elevate your TypeScript workflow with Zagora: a sleek, bulletproof toolkit for f
 - 🔒 **Type-Safe:** Full type inference across inputs, outputs, errors, context, optionals, and defaults.
 - ✋ **Ergonomic:** Pure functions with auto-filled defaults, optional args, and detailed diagnostics.
 - 🏠 **Familiar:** Echoes remote-RPC patterns from oRPC and tRPC, but focused on libraries, not apps.
-- ⚖️ **Unopinionated:** Zero assumptions - no routers, middlewares, or network dependencies.
+- ⚖️ **Unopinionated:** Zero assumptions - no routers, middlewares, or network concepts.
 - 🎁 **No Unwrapping:** Direct access to results, unlike `neverthrow` - no extra steps required.
 - 🤖 **Agents Ready:** Rules for LLMs with subtle nuances and where to be careful. [Read/get here](./AGENTS.md)
 
@@ -694,7 +694,7 @@ Creates a new Zagora instance.
 - `.context<T>(initial)` - Type the context with generic, and optionally set initial context
 - `.cache(adapter)` - Set cache adapter that should have `has`, `get`, `set`, methods
 - `.handler(fn)` - Set handler/procedure function
-- `.callable(runtimeContext?)` - Create callable procedure, context is deep merged with the initial context.
+- `.callable(opts?: { context?, cache? })` - Create callable procedure, context is deep merged with the initial context.
 
 ## Error Types
 

src/errors.ts

@@ -58,7 +58,7 @@ export function isZagoraError<T>(val: any): val is ZagoraError<T> {
 }
 
 export function createValidationError<ErrorKindNames = never>(
-  mode: "input" | "output" | "error data",
+  mode: "input" | "output" | "error data" | "env",
   issues: SchemaIssue[],
   key?: ErrorKindNames,
 ) {
@@ -115,28 +115,15 @@ export type ErrorHelpers<
     }
   : never;
 
-export type ErrorsMapPlain<TErrorsMap extends Record<string, AnySchema>> = {
-  [K in keyof TErrorsMap]: Prettify<
-    { kind: K } & InferSchemaOutput<TErrorsMap[K]>
-  >;
+export type InferSchemaMapPlain<
+  T extends Record<string, AnySchema>,
+  ResolveErr extends boolean,
+> = {
+  [K in keyof T]: ResolveErr extends true
+    ? Prettify<{ kind: K } & InferSchemaOutput<T[K]>>
+    : Prettify<InferSchemaOutput<T[K]>>;
 };
 
-// export type ErrorsMapResolved<
-//   TErrorsMap extends Record<string, AnySchema> | undefined,
-// > = TErrorsMap extends Record<string, AnySchema>
-//   ? ErrorsMapPlain<TErrorsMap>
-//   : undefined;
-
-export type ErrorsMapResolved<
-  TErrorsMap extends Record<string, AnySchema> | undefined,
-> = TErrorsMap extends Record<string, AnySchema>
-  ? {
-      [K in keyof TErrorsMap]: Prettify<
-        { kind: K } & InferSchemaOutput<TErrorsMap[K]>
-      >;
-    }
-  : undefined;
-
 export type ResolveErrorKindNames<TErrorsMap> = TErrorsMap extends Record<
   string,
   AnySchema