test(packaging): verify consumer TypeScript declarations across all entrypoints

[shettyvarun268]

Description

Adds consumer TypeScript declaration (.d.ts) verification to the packaging CI test (scripts/test-packaging.sh / npm run test:packaging) to ensure the published package compiles cleanly without skipLibCheck: true.

Previously, scripts/verify-exports.mjs only validated Node.js runtime loading (require() and import()), allowing broken or stripped @internal .d.ts imports (TS2724) or mismatched typesVersions paths (TS2307) to slip through CI undetected.

This PR:

1. Adds scripts/verify-types.mjs, which dynamically generates imports across all public entrypoints in package.json and runs npx tsc --noEmit --skipLibCheck false under both:
   • CommonJS / Legacy resolution (--module commonjs --moduleResolution node --esModuleInterop) to validate typesVersions
   • ESM / Dual resolution (--module nodenext --moduleResolution nodenext) to validate exports["..."]["types"]
2. Updates scripts/test-packaging.sh to install consumer TypeScript dependencies (typescript@5, @types/node, firebase-admin) and execute verify-types.mjs after verify-exports.mjs (and defaults $1 to ${1:-} so npm run test:packaging works locally without arguments).
3. Fixes 6 missing /index suffixes under typesVersions in package.json for ai and v2/ai subpaths caught by the new check.

Scenarios Tested

• Ran npm run test:packaging locally (passes all 62 entrypoints across CJS runtime, ESM runtime, CJS tsc, and NodeNext tsc).
• Verified negative test case: marking WireParamSpec as @internal immediately fails npm run test:packaging with error TS2724.
• Ran npm run lint (0 errors).

Release Notes

relnote: none

[gemini-code-assist]

Code Review

This pull request updates package exports in package.json to point to explicit index paths and introduces a new TypeScript declaration verification script (verify-types.mjs) to the packaging test pipeline. Feedback on the new verification script includes: executing the local tsc compiler directly with node instead of npx to ensure compatibility on Windows, using an anchored regular expression to safely strip leading ./ prefixes from export paths, and cleaning up the temporary verify-types.ts file before the script exits.

[shettyvarun268]

/gemini review

[gemini-code-assist]

Code Review

This pull request updates export paths in package.json to explicitly point to index files, cleans up build artifacts in the packaging script, and introduces a new verification script (verify-types.mjs) to validate TypeScript declarations and package exports. The review feedback suggests improving the robustness of the verification script by adding type checks for export targets and types paths to prevent potential runtime errors during string operations and path resolution.

[ajperel]

I will admit this is touching things that I am not an expert in. But AI think this is a great end-to-end test approach. Working with it a lot I have a few small suggestions to improve how it's done and one suggestion that we also introduce a fast fail case on build that should catch most (but maybe not all) problems so devs don't only catch this late in CI.

[ajperel]

🟡 Nit: Add upfront existence guard for tsc binary

If typescript fails to install or is hoisted unexpectedly, execFileSync throws a generic child process error. An upfront guard mirroring the pkgPath check on line 28 makes the diagnostic immediate and clear:

Suggested change

	const tscPath = path.resolve(process.cwd(), 'node_modules/typescript/bin/tsc');
	const tscPath = path.resolve(process.cwd(), "node_modules/typescript/bin/tsc");
	if (!fs.existsSync(tscPath)) {
	console.error(`❌ Could not find TypeScript compiler binary at ${tscPath}`);
	process.exit(1);
	}

[ajperel]

This is maybe getting too edge casey? AI does like to handle everything under the sun. Not sure though... we have had npm issues before.

[shettyvarun268]

Added this. Just 4 lines and helps with an early exit without printing long stack traces