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/connectors/sqlserver/dialect.test.ts

@@ -13,7 +13,7 @@ describe('KtxSqlServerDialect', () => {
     expect(dialect.formatTableName({ catalog: null, db: null, name: 'events' })).toBe('[events]');
   });
 
-  it('maps SQL Server types to KTX dimension types', () => {
+  it('maps SQL Server types to ktx dimension types', () => {
     expect(dialect.mapToDimensionType('datetime2')).toBe('time');
     expect(dialect.mapToDimensionType('decimal(18, 2)')).toBe('number');
     expect(dialect.mapToDimensionType('bigint')).toBe('number');