chore(cli): temporarily disable Sentry reporting for unclassified errors (#14750)

## Description

Part of the CLI error classification effort — see #14749 for full context.

Temporarily suppresses Sentry reporting for errors that haven't been classified yet. This is a safety net so that merging #14749 doesn't flood Sentry with noise while the ~35 follow-up package migration PRs are landing.

## Changes Made

- Added `UNCLASSIFIED` to `CliError.Code`
- Default error code fallback changed from `INTERNAL_ERROR` to `UNCLASSIFIED` in:
  - `cli.ts` (CLI v1 top-level catch)
  - `CliContext.ts` (CLI v1 task runner)
  - `withContext.ts` → `reportError` (CLI v2)
- `UNCLASSIFIED` is **not** in `SENTRY_REPORTABLE_CODES`, so these errors are silently tracked in PostHog but not sent to Sentry

## Rollback

Once all package migration PRs have landed, #14752 will remove `UNCLASSIFIED` and revert the fallback to `INTERNAL_ERROR`.

## Testing

- [x] Existing tests pass (only changes default string literals)

Author: FedeZara

packages/cli/cli/src/cli-context/TaskContextImpl.ts

@@ -12,6 +12,7 @@ import {
     TaskContext,
     TaskResult
 } from "@fern-api/task-context";
+
 import chalk from "chalk";
 
 import { reportError } from "../telemetry/reportError.js";

packages/cli/task-context/src/CliError.ts

@@ -57,7 +57,8 @@ export namespace CliError {
         ValidationError: "VALIDATION_ERROR",
         NetworkError: "NETWORK_ERROR",
         AuthError: "AUTH_ERROR",
-        ConfigError: "CONFIG_ERROR"
+        ConfigError: "CONFIG_ERROR",
+        Unclassified: "UNCLASSIFIED"
     } as const;
 }
 
@@ -73,7 +74,8 @@ const SENTRY_REPORTABLE: Record<CliError.Code, boolean> = {
     [CliError.Code.ValidationError]: false,
     [CliError.Code.NetworkError]: false,
     [CliError.Code.AuthError]: false,
-    [CliError.Code.ConfigError]: false
+    [CliError.Code.ConfigError]: false,
+    [CliError.Code.Unclassified]: false
 };
 
 export function shouldReportToSentry(code: CliError.Code): boolean {
@@ -93,7 +95,8 @@ function isNodeVersionError(error: unknown): boolean {
 /**
  * Resolves the effective error code: explicit override wins,
  * then auto-detects from known error types,
- * and falls back to INTERNAL_ERROR for truly unknown errors.
+ * and falls back to UNCLASSIFIED for unknown errors until all packages
+ * are migrated to the new error system.
  */
 export function resolveErrorCode(error: unknown, explicitCode?: CliError.Code): CliError.Code {
     if (explicitCode != null) {
@@ -108,5 +111,5 @@ export function resolveErrorCode(error: unknown, explicitCode?: CliError.Code):
     if (isNodeVersionError(error)) {
         return CliError.Code.EnvironmentError;
     }
-    return CliError.Code.InternalError;
+    return CliError.Code.Unclassified;
 }