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/check-boundaries.test.mjs

@@ -25,7 +25,7 @@ describe('scanFileContent', () => {
       [],
     );
     assert.deepEqual(
-      scanFileContent('packages/cli/src/prompts/memory_agent_bundle_ingest_work_unit.md', 'Write output for KTX.'),
+      scanFileContent('packages/cli/src/prompts/memory_agent_bundle_ingest_work_unit.md', 'Write output for ktx.'),
       [],
     );
   });
@@ -83,7 +83,7 @@ describe('scanFileContent', () => {
     );
   });
 
-  it('rejects old KTX LLM port declarations in context', () => {
+  it('rejects old ktx LLM port declarations in context', () => {
     const violations = [
       ...scanFileContent('packages/cli/src/context/agent/agent-runner.service.ts', 'export interface LlmProviderPort {}'),
       ...scanFileContent('packages/cli/src/context/scan/types.ts', 'export interface KtxScanLlmPort {}'),