feat: deduplicate repeated inline object types in generated output

Splits type generation into a 3-phase pipeline:
1. Collect TypeNodes from all queries
2. Build deduplication registry by fingerprinting object types
3. Generate TS types, replacing duplicates with references

Duplicate object types appearing across queries are extracted into
shared "Inline"-prefixed type aliases, reducing generated code size
and improving readability.

Author: kbrabrand