DMD-920 - Add package documentation for twinformat

Documents the snake_case JSON naming convention required by the Twin Format
specification and explains why the tagliatelle linter is disabled.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: vojtabiberle

internal/pkg/llm/twinformat/doc.go

@@ -0,0 +1,19 @@
+// Package twinformat implements the Twin Format specification for LLM data export.
+//
+// # JSON Output Format
+//
+// All JSON output from this package uses snake_case field names (e.g., "primary_key",
+// "consumed_by", "component_id") as required by the Twin Format specification for
+// LLM compatibility. This intentionally differs from Go's conventional camelCase.
+//
+// The tagliatelle linter is disabled at the package level in types.go for this reason.
+//
+// # Output Structure
+//
+// The export produces the following structure:
+//   - tables/*.json - Table definitions with lineage dependencies
+//   - transformations/*.json - Transformation configs with code blocks
+//   - buckets/index.json - Bucket index with statistics
+//   - lineage/graph.jsonl - Lineage edges in JSONL format
+//   - manifest-extended.json - Project metadata and statistics
+package twinformat