perf(cli): keep the env-graph barrel out of the CLI entry point

Splitting the commands off left a 559KB shared chunk still loaded on every
invocation. That chunk was env-graph + the @env-spec parser + clack prompts
+ ansis, merged together because the entry reached the env-graph barrel
through three edges:

- helpers/error-checks.ts imports { EnvGraph, FileBasedDataSource } from the
  barrel, but the entry only ever wanted InvalidEnvError from that module.
  Moved that class to its own leaf module and pointed the entry at it.
- lib/formatting.ts imported ConfigItem and VarlockError as values, though
  both are only used as parameter annotations. Made it an `import type`, so
  the edge is erased at compile time.
- helpers/telemetry-usage-context.ts already deep-imports env-graph/lib/errors,
  which is a leaf (its only import is my-dash), so it costs nothing.

error-checks.ts re-exports InvalidEnvError, so no other caller changes. The
class is still defined exactly once in the bundle, which is what keeps the
entry's `instanceof InvalidEnvError` catch working.

Entry static closure: 1029KB -> 320KB.

Author: theoephraim

packages/varlock/src/cli/cli-executable.ts

@@ -9,7 +9,7 @@ import { VARLOCK_BANNER_COLOR } from '../lib/ascii-art';
 import { CliExitError } from './helpers/exit-error';
 import { fmt } from './helpers/pretty-format';
 import { trackCommand, trackInstall } from './helpers/telemetry';
-import { InvalidEnvError } from './helpers/error-checks';
+import { InvalidEnvError } from './helpers/invalid-env-error';
 import { isArgError, toCliExitError } from './helpers/arg-errors';
 import { checkBunVersion } from '../lib/check-bun-version';
 import { checkLocalVersionMismatch } from '../lib/check-local-version';

packages/varlock/src/cli/helpers/error-checks.ts

@@ -5,6 +5,9 @@ import {
   LoadingError, ParseError, VarlockError,
 } from '../../env-graph/lib/errors';
 import { CliExitError } from './exit-error';
+import { InvalidEnvError } from './invalid-env-error';
+
+export { InvalidEnvError };
 
 function showErrorLocationDetails(err: VarlockError) {
   if (!err.location) return;
@@ -130,14 +133,6 @@ export function showPluginWarnings(envGraph: EnvGraph) {
   }
 }
 
-export class InvalidEnvError extends Error {
-  constructor() {
-    super('Resolved config/env did not pass validation');
-  }
-  getFormattedOutput() {
-    return `\n💥 ${ansis.red(this.message)} 💥\n`;
-  }
-}
 
 export function checkForConfigErrors(envGraph: EnvGraph, opts?: {
   showAll?: boolean;

packages/varlock/src/cli/helpers/invalid-env-error.ts

@@ -0,0 +1,17 @@
+import ansis from 'ansis';
+
+/**
+ * Thrown when resolved config fails validation.
+ *
+ * Kept in its own module (rather than alongside the `checkFor*` helpers in
+ * `error-checks.ts`) so the CLI entry point can catch it without importing
+ * those helpers, which pull in the whole env-graph barrel.
+ */
+export class InvalidEnvError extends Error {
+  constructor() {
+    super('Resolved config/env did not pass validation');
+  }
+  getFormattedOutput() {
+    return `\n💥 ${ansis.red(this.message)} 💥\n`;
+  }
+}

packages/varlock/src/lib/formatting.ts

@@ -1,7 +1,7 @@
 import ansis, { type AnsiColors, type AnsiStyles } from 'ansis';
 import _ from '@env-spec/utils/my-dash';
 
-import { ConfigItem, VarlockError } from '../env-graph';
+import type { ConfigItem, VarlockError } from '../env-graph';
 import { redactString } from '../runtime/lib/redaction';
 
 type ColorMod = AnsiStyles | AnsiColors;