Fix negative IOB on fresh installs (#898)

[dnzxy]

Summary

This PR fixes cases where negative IOB can occur when pump history contains a resume without a preceding suspend (e.g. fresh installs of newly onboarded Trio users).

Fixes: #898

Changes

The logic now detects resume-only states within the DIA (duration of insulin action) window and injects a simulated suspend event 1s before the resume only if no real suspend exists in the relevant history window. This gives oref a safe baseline without altering valid pump history.

[marionbarker]

Test

Summary: TBD

Configuration

• Use an older version of the pod rPi simulator (commit 4e2a622) that does not properly report pods as suspended in certain cases.
• Use an older version of OmniBLE (commit b65dbfc2e) so can present resume without suspend.

Test 1

Delete Trio for SE 3rd gen phone running iOS 26.

• build Trio dev (0.6.0.31) (with modified OmniBLE) to the phone
• accept all default settings except set basal rates to 1 U/hr, CR to 10 g/U and ISF to 50 mg/dL/U
  • for the initial attempt I left basal at 0.1 U/hr and the negative IOB was -0.21; so started over with higher basal rates

Add Glucose simulator as CGM and rPi DASH as pump.
Observe IOB

Time	IOB	Comment
14:16	0	pod connected
14:19	-1.56	closed loop disabled
14:24	-1.56	flip from disable to enable
14:25	-1.51	first loop, TB set
14:32	-1.41	end test

Test 2

Delete Trio for SE 3rd gen phone running iOS 26.

• build Trio fix-negative-iob-after-onboarding, commit 6e5e780, with modified OmniBLE to the phone
• accept all default settings except set basal rates to 1 U/hr, CR to 10 g/U and ISF to 50 mg/dL/U

Add Glucose simulator as CGM and rPi DASH as pump.
Observe IOB

Time	IOB	Comment
14:42	0	pod connected
14:51	-1.56	closed loop disabled

no difference. Make sure I really have the new build.
Do a clean build folder, close and open workspace
rebuild and no difference.

Do another delete Trio and rebuild again.
Repeat the test.
Same result.

[marionbarker]

Test Summary

Initial look is good - no unexpected negative IOB after pump and CGM are attached to a fresh build.
I'll let this phone run in closed Loop for a while to see if unexpected negative IOB show up later in the history.

Test 3

Earlier tests were done before the PR was ready for testing.

Delete Trio from SE 3rd gen phone running iOS 26.

• build Trio commit b7d42e3 (this pr) to the phone
• accept all default settings except set basal rates to 1 U/hr, (SMB are disabled)

Add Glucose simulator as CGM and rPi DASH as pump.

• TBR = temp basal rate
• SBR = scheduled basal rate

Observe IOB

Time	IOB	Comment
19:46	0	rPi pod connected
19:50	0	first new CGM reading, closed loop still disabled
19:57	0	flip from closed loop from disable to enable
20:05	0	looping, TBR (0.55 U/hr) < SBR (1.0 U/hr) because of glucose history
20:08	-0.05 U	looping, this small negative IOB is because TBR still 0.55 U/hr
20:13	-0.1 U	looping, TBR is now same as SBR, 1.0 U/hr
20:23	-0.1 U	looping, TBR still same as SBR, 1.0 U/hr