v1.4

Streaming Encoding Extension (Section 6b)

• [?] deferred count marker for section headers
• ## _summary trailer provides counts after data
• Zero-buffering encode with O(1) memory per row
• Backward compatible (old decoders treat _summary as empty section)
• 5 streaming conformance fixtures (61 total)

Other changes

• Streaming guide (docs/guide/streaming.md)
• Proxy guide updated with streaming progress and roadmap
• Updated benchmark numbers across all docs