[E97] Gemma 4 Generation + Ollama Parity (follow-up to E93-4) #742

Epic E97: Gemma 4 Generation + Ollama Parity (follow-up to E93-4)

Tasks

• T97.1.1 Extend cmd/gemma4_e2e with -mode=generate and -prompt flags
• T97.1.2 Add generate mode to Spark manifest
• T97.1.3 Run generation on DGX and record result
• T97.2.1 Evaluate Ollama Gemma 4 availability
• T97.2.2 Parity harness: shared prompt + top-1 extraction
• T97.2.3 Run parity on DGX and document
• T97.3.1 Mark T93.4.2 complete when E97.1 lands

Synced from plan.md.