[Performance] Memoize ciPlatform function

[gonzaloriestra]

Why is this change necessary?

The ciPlatform function is called frequently, especially during analytics collection, and performs multiple environment variable lookups and metadata assembly. Since these environment variables are static during a single CLI command execution, caching the result improves performance by avoiding repeated work.

How to test your changes?

CI

Checkbox

• I've added a changeset (if applicable)
• I've updated the documentation (if applicable)

Expected performance impact

Eliminates redundant environment variable scans and metadata object creation in high-frequency analytics paths. While the absolute time saved per call is small (micro-optimizations), the cumulative effect across all commands (which all report analytics) contributes to a snappier CLI experience.

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PR created automatically by Jules for task 2348603642377422416 started by @gonzaloriestra

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[github-actions]

Differences in type declarations

We detected differences in the type declarations generated by Typescript for this branch compared to the baseline ('main' branch). Please, review them to ensure they are backward-compatible. Here are some important things to keep in mind:

• Some seemingly private modules might be re-exported through public modules.
• If the branch is behind main you might see odd diffs, rebase main into this branch.

New type declarations

We found no new type declarations in this PR

Existing type declarations

packages/cli-kit/dist/public/node/context/local.d.ts

@@ -132,6 +132,11 @@ export declare function cloudEnvironment(env?: NodeJS.ProcessEnv): {
  * @returns A promise that resolves with the value.
  */
 export declare function hasGit(): Promise<boolean>;
+/**
+ * Resets the memoized CI platform value.
+ * This is useful for testing purposes.
+ */
+export declare function _resetCIPlatformCache(): void;
 /**
  * Gets info on the CI platform the CLI is running on, if applicable.
  *