SHACHI-patterns/INDEX.md (76 lines)

• Umbrella index for cross-platform Dreamcast development patterns
• Status lifecycle: theoretical → attempted → validated → refined
• 5 categories: Streaming (STR-001, STR-002), Rendering (REN-001 to REN-004), Textures (TEX-001, TEX-002), Audio (AUD-001), Architecture (ARC-001, ARC-002)
• All 10 patterns currently at theoretical status
• Dreamcast: 10 patterns; PS2: 0 patterns currently
• Linked to dc/patterns/INDEX.md and ps2/patterns/INDEX.md
• Confidence separate from status