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.

scripts/run-ktx.mjs

@@ -161,13 +161,13 @@ export async function runWorkspaceKtx(argv, options = {}) {
   if (needsBuild) {
     stderr.write(
       binExists
-        ? 'KTX CLI build output is stale. Rebuilding it now with `pnpm run build`...\n'
-        : 'KTX CLI build output is missing. Building it now with `pnpm run build`...\n',
+        ? 'ktx CLI build output is stale. Rebuilding it now with `pnpm run build`...\n'
+        : 'ktx CLI build output is missing. Building it now with `pnpm run build`...\n',
     );
     const buildExitCode = await runCommand('pnpm', ['run', 'build'], { cwd: rootDir, env: commandEnv });
     if (buildExitCode !== 0) {
       stderr.write(
-        '\nKTX CLI build failed. Run `pnpm run setup:dev` from the KTX directory, then retry this command.\n',
+        '\nktx CLI build failed. Run `pnpm run setup:dev` from the ktx directory, then retry this command.\n',
       );
       return buildExitCode;
     }