Add Gemma 3n to KerasHub#2404

Draft

harshaljanjani wants to merge 11 commits intokeras-team:masterfrom

harshaljanjani:gemma3n

Commits on Sep 16, 2025

init: Added some stuff, tons to go
harshaljanjani
committed

Commits on Oct 11, 2025

Commits on Oct 31, 2025

feat: Add checkpoint conversion script (1 preset)
harshaljanjani
committed

Commits on Nov 4, 2025

Commits on Nov 5, 2025

refactor: Gemma3nCausalLM and update tests
harshaljanjani
committed

Commits on Nov 7, 2025

feat: Complete TODO for CausalLM
harshaljanjani
committed

Commits on Nov 8, 2025

nit: Minor changes
harshaljanjani
committed