refactor: enforce ktx naming and AGENTS.md compliance sweep (#289)

Align the tree with AGENTS.md/CLAUDE.md conventions:

- Rewrite user-facing strings, docs, and tests to lowercase `ktx`
  (no bare uppercase `KTX` tokens remain outside literal identifiers).
- Drop the legacy `historicSql` migration path and its now-unused
  helpers, per the no-backward-compat rule.
- Remove `as unknown as` / `any` casts: narrow `BaseTool` generics to
  `z.ZodObject`, add a typed `createLookerClient`, and delete the dead
  `getParametersSchema`/`toAnthropicFormat` pre-AI-SDK helpers.
- Use `InvalidArgumentError` for Commander parse failures.
- Finish the adapter→connector prose conversion in the `ktx.yaml` docs
  while keeping the literal `adapters` config key.

packages/cli/test/context/test/make-local-git-repo.ts

@@ -20,7 +20,7 @@ export async function makeLocalGitRepo(fixtureDir: string, destRoot: string): Pr
   await git.init();
   await git.raw(['checkout', '-B', 'main']);
   await git.addConfig('user.email', 'test@ktx.local');
-  await git.addConfig('user.name', 'KTX Test');
+  await git.addConfig('user.name', 'ktx Test');
   await git.add('.');
   await git.commit('initial');
   const commit = async (message: string): Promise<string> => {