Regression: compression threshold settings now accept negative values

[acoliver]

Summary

The branch for issue #1898 appears to fix the idle-timeout problem, but it also introduces an unrelated validation regression in packages/core/src/settings/settingsRegistry.ts.

Problem

The validation for compression-threshold and compression.density.optimizeThreshold no longer enforces a lower bound of 0.

Current conditions in settingsRegistry.ts now effectively allow any numeric value less than or equal to 1 because the lower-bound check was replaced with a constant true.

That means negative values are now accepted for settings that are documented and consumed as 0..1 thresholds.

Why this matters

• Negative compression-threshold values can change compression behavior in ways the rest of the code does not expect.
• Negative compression.density.optimizeThreshold values can be persisted and treated as valid user settings even though the setting is documented as 0..1.
• This change is unrelated to the stream idle timeout fix and should be corrected separately after merge.

Follow-up work

1. Restore the lower-bound validation for both settings so valid values are 0 through 1.
2. Add regression tests that prove negative values are rejected.
3. Verify whether stream-idle-timeout-ms should also be surfaced in the CLI settings schema/help surfaces, since the runtime and ephemeral setting paths appear to support it but I did not confirm full schema surfacing.

Notes

• This was spotted during review of the issue1898 branch.
• I did not run tests as part of the review.

[coderabbitai]

🔗 Related PRs

#1449 - fix(compression): tune HD compression to preserve more context (Fixes #1448) [merged]
#1486 - fix(compression): raise default compressionThreshold from 0.5 to 0.85 (Fixes #1483) [merged]
#1818 - fix(core): enforce hard-limit compression fallback + diagnostics (Fixes #1791) [merged]
#1827 - fix(compress): distinguish no-op, recent, and failed outcomes (Fixes #1792) [merged]
#1899 - fix(stream): make idle timeout configurable and raise default to 10 min (Fixes #1898) [closed]

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