Default gradient_clipping to 1.0 (#8068)
## Summary
- Change `GRADIENT_CLIPPING_DEFAULT` from `0.` (disabled) to `1.0`.
## Motivation
With the old default, configs that omit `gradient_clipping` run
unclipped. Most RL/LLM training (and the FSDP2 reference) clip at `1.0`;
this avoids silently-unclipped runs. Isolated into its own PR since it
is a default behavior change.
## Test plan
- [ ] Init without `gradient_clipping` -> effective clip norm is `1.0`.
- [ ] Explicit `gradient_clipping: 0.0` still disables clipping
(override respected).
Made with [Cursor](https://cursor.com)
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Signed-off-by: Olatunji Ruwase <tunji.ruwase@snowflake.com>
Co-authored-by: Cursor <cursoragent@cursor.com>
