Add --country flag to store create dev

[amcaplan]

What

Adds a --country flag to shopify store create dev, implementing the country piece of shop/world#22968, and shares the flag — definition, validation, and error message — with shopify store create preview.

• flags.ts exports a single shared countryFlag constant (env SHOPIFY_FLAG_STORE_COUNTRY). Its parse normalizes the value to trimmed uppercase and validates the two-letter shape, throwing a consistent AbortError before a command's run body executes. isCountryCode and the error message are internal implementation details of the flag.
• Both store create dev and store create preview reference this one countryFlag, so validation and error output are identical and defined in exactly one place — no per-command if-checks.
• store create dev threads --country into createDevStore, which sends it to the BP createAppDevelopmentStore mutation and surfaces it in JSON and success output.

Notes

• Validation now lives in the flag's parse (oclif enforces it), rather than being duplicated in each command.
• The preview command's env var changed from SHOPIFY_FLAG_PREVIEW_STORE_COUNTRY to the shared SHOPIFY_FLAG_STORE_COUNTRY. The --country flag is new/unreleased and the command is hidden, so there's no external impact.
• Command is hidden; no changeset.
• Tests pass (command + service); manifest updated for the env-var change.

[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/private/node/constants.d.ts

@@ -6,6 +6,7 @@ export declare const environmentVariables: {
     doctor: string;
     enableCliRedirect: string;
     env: string;
+    firstPartyDev: string;
     noAnalytics: string;
     optOutInstrumentation: string;
     appAutomationToken: string;

packages/cli-kit/dist/private/node/session.d.ts

@@ -90,7 +90,6 @@ export declare function setLastSeenUserIdAfterAuth(id: string): void;
  */
 export declare function getLastSeenAuthMethod(): Promise<AuthMethod>;
 export declare function setLastSeenAuthMethod(method: AuthMethod): void;
-export declare function setCommandSessionId(sessionId: string | undefined): void;
 export interface EnsureAuthenticatedAdditionalOptions {
     noPrompt?: boolean;
     forceRefresh?: boolean;

packages/cli-kit/dist/public/node/base-command.d.ts

@@ -16,7 +16,6 @@ declare abstract class BaseCommand extends Command {
     protected parse<TFlags extends FlagOutput & {
         path?: string;
         verbose?: boolean;
-        'auth-alias'?: string;
     }, TGlobalFlags extends FlagOutput, TArgs extends ArgOutput>(options?: Input<TFlags, TGlobalFlags, TArgs>, argv?: string[]): Promise<ParserOutput<TFlags, TGlobalFlags, TArgs> & {
         argv: string[];
     }>;

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

@@ -39,9 +39,6 @@ export declare const globalFlags: {
 export declare const jsonFlag: {
     json: import("@oclif/core/interfaces").BooleanFlag<boolean>;
 };
-export declare const authAliasFlag: {
-    'auth-alias': import("@oclif/core/interfaces").OptionFlag<string | undefined, import("@oclif/core/interfaces").CustomOptions>;
-};
 /**
  * Builds a  flag that only accepts a valid port number. The flag parses its
  * value as an integer and rejects anything that isn't a whole number between 1 and

packages/cli-kit/dist/public/node/session.d.ts

@@ -22,19 +22,6 @@ export type AccountInfo = UserAccountInfo | ServiceAccountInfo | UnknownAccountI
  * @param userId - User identifier to report on the command analytics event.
  */
 export declare function setLastSeenUserId(userId: string): void;
-/**
- * Finds a stored Shopify account session by alias without changing the current session.
- *
- * @param alias - The account alias to find.
- * @returns The matching session ID, or undefined if no session matches.
- */
-export declare function findSessionIdByAlias(alias: string): Promise<string | undefined>;
-/**
- * Selects a stored Shopify account session by alias for the current command process.
- *
- * @param alias - The account alias to select. Passing undefined clears the command selection.
- */
-export declare function setCurrentSessionAlias(alias?: string): Promise<void>;
 interface UserAccountInfo {
     type: 'UserAccount';
     email: string;

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

@@ -63,6 +63,13 @@ export declare function alwaysLogAnalytics(env?: NodeJS.ProcessEnv): boolean;
  * @returns True if SHOPIFY_CLI_ALWAYS_LOG_METRICS is truthy.
  */
 export declare function alwaysLogMetrics(env?: NodeJS.ProcessEnv): boolean;
+/**
+ * Returns true if the CLI User is 1P.
+ *
+ * @param env - The environment variables from the environment of the current process.
+ * @returns True if SHOPIFY_CLI_1P is truthy.
+ */
+export declare function firstPartyDev(env?: NodeJS.ProcessEnv): boolean;
 /**
  * Returns true if the CLI can run the "doctor-release" command.
  *