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/src/cli-runtime.ts

@@ -61,7 +61,7 @@ export function packageInfoFromJson(packageJson: unknown): KtxCliPackageInfo {
     typeof packageJson.name !== 'string' ||
     typeof packageJson.version !== 'string'
   ) {
-    throw new Error('Invalid KTX CLI package metadata');
+    throw new Error('Invalid ktx CLI package metadata');
   }
 
   return {
@@ -77,7 +77,7 @@ async function runInit(args: { projectDir: string; force: boolean }, io: KtxCliI
     force: args.force,
   });
 
-  io.stdout.write(`Initialized KTX project at ${result.projectDir}\n`);
+  io.stdout.write(`Initialized ktx project at ${result.projectDir}\n`);
   io.stdout.write(`Config: ${result.configPath}\n`);
   io.stdout.write(`Commit: ${result.commitHash ?? 'none'}\n`);
   return 0;