Support CQL initialExpression population on questionnaires

[delcroip]

IMPORTANT: Where possible all PRs must be linked to a Github issue

Import of the EMCARE app logic done by AI

Engineer Checklist

• I have written Unit tests for any new feature(s) and edge cases for bug fixes
• (NA) I have added any strings visible on UI components to the strings.xml file
• I have updated the CHANGELOG.md file for any notable changes to the codebase
• I have run ./gradlew spotlessApply and ./gradlew spotlessCheck to check my code follows the project's style guide (java 21)
• I have built and run the FHIRCore app to verify my change fixes the issue and/or does not break the app
• I have checked that this PR does NOT introduce breaking changes that require an update to Content and/or Configs? If it does add a sample here or a link to exactly what changes need to be made to the content.

Code Reviewer Checklist

• I have verified Unit tests have been written for any new feature(s) and edge cases
• I have verified any strings visible on UI components are in the strings.xml file
• I have verifed the CHANGELOG.md file has any notable changes to the codebase
• I have verified the solution has been implemented in a configurable and generic way for reuseable components
• I have built and run the FHIRCore app to verify the change fixes the issue and/or does not break the app

CQL initialExpression Population on Questionnaires

Field	Value
Status	Implemented (pending on-device verification)
Repos	openSRP FHIRCore Android (android/)
Related	feature/register-tricc.md (PlanDefinition $apply / CQL usage precedent)

Valid status values: Draft → Approved → Implemented → Superseded.

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Part I — Business spec

1. Problem

SDC Questionnaires support item.extension initialExpression to pre-populate an answer from a
computed expression instead of a static initial value. TRICC-generated content expresses these
computations in CQL (language = text/cql-identifier or text/cql), referencing define
statements in a Library linked to the Questionnaire via a cqf-library extension. Before this
change, the app only evaluated FHIRPath-based initialExpressions (via the Android FHIR SDK's
built-in ResourceMapper.populate) — CQL-based ones were silently ignored, so any TRICC form relying
on a CQL default (e.g. a computed BMI, a derived risk flag, a value copied from an earlier
encounter) opened with that field blank.

2. Goal

When a Questionnaire declares one or more cqf-library extensions, evaluate any CQL
initialExpression items against that library before the SDC library populates the
QuestionnaireResponse, so CQL-derived defaults appear exactly like any other prepopulated answer.

3. Decisions

Topic	Decision
Supported languages	text/cql-identifier and text/cql only (FHIRPath initialExpression continues to go through the SDC library unchanged).
cqf-library extension value types	Support valueCanonical, valueUri, and valueString (TRICC/authoring tools are inconsistent about which type they emit).
When to run	Only when opening a new response — skipped when reopening an editable/read-only/summary/draft response, so previously saved answers are never overwritten by a fresh CQL evaluation.
Evaluation context	FhirOperator.evaluateLibrary per distinct library URL, with the launch-context subject resource as the CQL context resource, and patient/encounterid passed as CQL parameters when those resources are present in the launch context.
Conflict with SDC library	initial and initialExpression cannot coexist on the same item per the SDC populate contract, so once a CQL value is resolved, the initialExpression extension is removed from the item and replaced with a plain initial value carrying the CQL result.
Failure handling	Per-library evaluation failures are caught and logged (Timber.e); they do not block loading the rest of the questionnaire or other libraries' expressions.

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Part II — Technical spec

4. Where it lives

Area	Location
cqf-library value extraction (multi-type)	engine/src/main/java/org/smartregister/fhircore/engine/util/extension/QuestionnaireExtension.kt — cqfLibraryIds(), cqfLibraryUrls(), private Extension.cqfLibraryValue()
CQL initial-expression evaluation	quest/src/main/java/org/smartregister/fhircore/quest/ui/questionnaire/QuestionnaireViewModel.kt — evaluateCqlInitialExpressions, collectCqlInitialExpressionItems, applyCqlExpressionResultsToInitial
Call site	QuestionnaireViewModel questionnaire-loading path, invoked before fetchRepositoryQuestionnaireResponse/populate, gated by a willLoadSavedResponse check
Tests	quest/src/test/java/org/smartregister/fhircore/quest/ui/questionnaire/QuestionnaireViewModelTest.kt

5. Flow

Open questionnaire
        │
        ▼
questionnaire.cqfLibraryUrls()  -- any cqf-library extensions?
        │ none                         │ one or more
        ▼                              ▼
  (unchanged SDC populate path)   collectCqlInitialExpressionItems()
                                        -- walk item tree, gather distinct
                                           CQL initialExpression strings
                                        │
                                        ▼
                                  build data Bundle from launchContextResources
                                  + Parameters (patient / encounterid, when present)
                                        │
                                        ▼
                                  for each distinct library URL:
                                    fhirOperator.evaluateLibrary(url, subjectRef,
                                        inputParameters, dataBundle, expressionSet)
                                        │
                                        ▼
                                  applyCqlExpressionResultsToInitial()
                                    -- for each item whose initialExpression
                                       matches a returned Parameters entry:
                                       remove initialExpression extension,
                                       set item.initial = [resultValue]
                                        │
                                        ▼
                                  ResourceMapper.populate() runs normally,
                                  now seeding these items from `initial`

6. Notable implementation details

• The CQL subject resource is chosen by matching questionnaire.subjectType against the
  launchContextResources list, falling back to the first launch-context resource if no type match
  is found.
• Only items whose initialExpression.language is in {text/cql-identifier, text/cql} are
  collected/evaluated; FHIRPath and other languages pass through untouched.
• Parameters.getParameter(exprName) results may come back as either .value or .resource
  depending on the CQL return type — both are checked.
• Item tree walking is recursive (item.item) so nested groups are covered.

7. Success criteria

1. A Questionnaire with a CQL initialExpression referencing a linked Library opens with that
   field pre-filled from the CQL evaluation result.
2. Reopening a previously saved (editable/read-only/summary/draft) response does not re-run CQL
   evaluation or overwrite the saved answer.
3. A Questionnaire with no cqf-library extension is unaffected (no behavior change, no performance
   cost).
4. A failure evaluating one library does not prevent the questionnaire from opening or other
   libraries' expressions from being evaluated.

8. Open items

• Not yet verified on-device (unit-tested only) — confirm real TRICC-generated Library/CQL content
  populates as expected on a physical device/emulator, including timing relative to CarePlan/Task
  launch-context loading.