CASSNODEJS-8: First TypeScript PR: Massive rename

[SiyaoIsHiding]

A lot of things broke, but don't panic!
This is the first PR for the typescript migration, mainly for the file extension rename, so that git diff will actually work in the future.
A very simple tsconfig is included so that you can at least run a command like npx ts-mocha test/unit/metadata-tests.ts to ensure things mostly work so far.

[SiyaoIsHiding]

GH does not allow me to request @toptobes 's review, but I'd appreciate it

[Copilot]

Pull request overview

This is the first PR in a planned TypeScript migration of the Node.js Cassandra driver. The bulk of the change is a mechanical rename of .js source and test files to .ts so that future code-level migration diffs remain readable in git history. A minimal tsconfig.json and the ts-mocha/typescript devDependencies are added so the renamed files can still be exercised individually via npx ts-mocha. The file contents are essentially untouched aside from dropping .js extensions in internal require(...) calls and (in package.json) removing the "types" field.

Changes:

• Renamed nearly all lib/**/*.js, test/**/*.js, and index.js to .ts and removed .js suffixes from internal require() paths.
• Added tsconfig.json (CommonJS, ES2015, allowJs, declaration) and added ts-mocha/typescript as devDependencies.
• Removed the "types": "./index.d.ts" entry from package.json.

Reviewed changes

Copilot reviewed 25 out of 230 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
tsconfig.json	New minimal TS config; only includes lib/**/*.ts and index.ts (excludes tests).
package.json	Adds ts-mocha/typescript devDeps; drops types field.
index.ts	Renamed from index.js; same exports.
lib/**/*.ts	Renamed from .js; require paths updated to drop .js.
test/unit//*.ts, test/integration//.ts, test/other/**/.ts	Test files renamed from .js; require paths updated.

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[SiyaoIsHiding]

Correct, but we will fix those later, because we will add roll-up and api-extractor.

[SiyaoIsHiding]

Correct, we will need to fix those scripts and other project setup later.