[chmjkb]

Description

Moves the Moonshine, Moonshine streaming and privacy-filter state dict hooks onto the shared weight helpers, and adds reshapeWeight.

• reshapeWeight: changes the shape only. No copy, no conversion; the tensor keeps its dtype and byteLength. Mismatched element counts throw CHECKPOINT_MISMATCH.
• Moonshine (+16 / −61): q/k/v fusion and cross-attention q/kv use concatRows + scaleWeight. stackRows is gone.
• Moonshine streaming (+7 / −8): gets the same q/k/v change through the shared fuseQkv. gamma + 1 stays f32 on purpose (rounding it to f16 would lose precision on devices without shader-f16), as do exp(log_k) and the all-ones CMVN weight.
• privacy-filter (+17 / −68): its private lazyF32/concatRows/column split are gone. Gate/up is splitCols + reshapeWeight, down_proj is reshapeWeight. The quantized path is untouched: quantized files skip this hook.
• The F16 safetensors builder used by the weight and hook tests is now one shared helper, test/core/weights/checkpoint.ts.

Names, shapes and byteLengths reaching the models are unchanged, so the hosted files load as before. F16 checkpoints now stay f16 through these hooks.

Introduces a breaking change?

• Yes
• No

Type of change

• Bug fix (change which fixes an issue)
• New feature (change which adds functionality)
• Documentation update (improves or adds clarity to existing documentation)
• Performance (kernel tuning, graph building, anything related to performance)
• Other (chores, tests, code style improvements etc.)

Testing instructions

1. pnpm typecheck && pnpm lint && pnpm --filter runntime test:unit (923 pass)
2. New tests: test/zoo/{moonshine,moonshine-streaming,privacy-filter}/stateDictHooks.test.ts, each on F32 and F16 synthetic checkpoints, values against hand-worked math. reshapeWeight cases in test/core/weights/transforms.test.ts.
3. pnpm --filter runntime test:gpu: 1439 passed, 16 expected failures.

Related issues

Part of #70. Stacked on #76.

Checklist

• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have updated the documentation accordingly
• My changes generate no new warnings

Additional notes

The only hosted privacy-filter file is int8, so its changed float path only runs when someone loads the official HF checkpoint.