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.

docs/release.md

@@ -1,4 +1,4 @@
-# KTX release runbook
+# ktx release runbook
 
 This runbook covers the maintainer workflow for publishing `@kaelio/ktx` to
 npm through GitHub Actions. The workflow uses semantic-release to choose the
@@ -36,7 +36,7 @@ Before you publish, confirm these requirements:
   publish the first stable version as `0.1.0`.
 
 semantic-release doesn't support choosing an arbitrary first `0.x` stable
-release. If KTX has no stable tag yet and you need the first stable release to
+release. If **ktx** has no stable tag yet and you need the first stable release to
 be `0.1.0`, create and push the baseline tag once before running the live
 stable workflow:
 
@@ -46,7 +46,7 @@ git tag v0.0.0 "${root_commit}"
 git push origin v0.0.0
 ```
 
-KTX follows the same versioning schema as the main Kaelio release workflow:
+**ktx** follows the same versioning schema as the main Kaelio release workflow:
 breaking-change and `major` commit markers create a minor release, not an
 automatic major release. A major version requires an intentional manual release
 path.