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/command-tree.test.ts

@@ -47,7 +47,7 @@ describe('walkCommandTree', () => {
 
   it('captures required, optional, and variadic arguments', () => {
     const command = new Command('scan')
-      .argument('<connectionId>', 'KTX connection id')
+      .argument('<connectionId>', 'ktx connection id')
       .argument('[schemas...]', 'Schemas');
 
     expect(walkCommandTree(command).arguments).toEqual(['<connectionId>', '[schemas...]']);
@@ -56,7 +56,7 @@ describe('walkCommandTree', () => {
   it('walks registered commands without applying hidden-command policy', () => {
     const root = new Command('ktx');
     root.command('scan', { hidden: true }).description('Run a standalone connection scan');
-    const ingest = root.command('ingest').description('Build or inspect KTX context');
+    const ingest = root.command('ingest').description('Build or inspect ktx context');
     ingest.command('run', { hidden: true }).description('Run local ingest by adapter');
     ingest.command('watch', { hidden: true }).description('Open a stored visual report');
     ingest.command('status').description('Print status');