Fix multi-component stratifier alignment for list + scalar

[lukedegruchy]

This branch fixes a $evaluate-measure stratifier defect (CDO-715) in which a boolean-basis stratifier composed of one multi-value (list) component and one scalar component emitted disjoint single-component strata instead of strata containing a value from every declared component. The fix generalizes the existing "function row key" alignment pass — previously applied only to Map<?, ?> (function) component results — so it also collects alignment row keys from Iterable<?> (list) component results, then expands scalar components onto those keys. As a side effect, the empty-list / empty-map case now suppresses the affected subject's stratum contribution entirely when the stratifier as a whole produces alignment rows, matching the existing single-component empty-list semantics.

1. Generalize collectFunctionRowKeys → collectAlignmentRowKeys, with parallel handling for Iterable<?> results that emits (subject | iterableElement(value, index)) row keys.
2. Rename expandScalarToMatchFunctionRowKeys → expandScalarToAlignmentRowKeys and route scalar expansion through the unified alignment-keys map so list+scalar mixes align the same way function+scalar mixes already did.
3. Add an empty-alignment-rows guard: when the stratifier overall has multi-value components but a particular subject produced none (empty Map / empty List), that subject now contributes zero strata instead of falling back to a subject-only scalar row.
4. Extract per-entry alignment logic into a collectAlignmentRowKeysForEntry helper to keep cognitive complexity within Sonar limits after the new branch was added.
5. Add a new R4 fixture (CohortBooleanMultiComponentListScalarStrat) plus single-subject and multi-subject tests covering the (encounter-status list × gender scalar) tuple expansion across the existing test patient set.

Worked example

CQL expressions (LibrarySimple.cql) — one returns a per-patient list, the other returns a per-patient scalar:

define "Distinct Encounter Statuses":
    distinct([Encounter] E return E.status)

define "Gender Stratification String":
    if Patient.gender = 'male' then 'male' else 'female'

For Patient/patient-9 (two Encounters with statuses finished and in-progress, gender male) these evaluate to:

"Distinct Encounter Statuses"   → { 'finished', 'in-progress' }   // List<String>
"Gender Stratification String"  → 'male'                          // String

Measure stratifier — two components, one referencing the list expression, one referencing the scalar:

"stratifier": [{
  "code": { "text": "Encounter Status and Gender" },
  "component": [
    {
      "code": { "text": "Encounter Status" },
      "criteria": { "language": "text/cql.identifier",
                    "expression": "Distinct Encounter Statuses" }
    },
    {
      "code": { "text": "Gender" },
      "criteria": { "language": "text/cql.identifier",
                    "expression": "Gender Stratification String" }
    }
  ]
}]

MeasureReport stratum — before the fix (broken: three single-component strata, gender never appears alongside encounter status):

"stratifier": [{
  "code": [{ "text": "Encounter Status and Gender" }],
  "stratum": [
    { "component": [{ "code": { "text": "Encounter Status" },
                      "value": { "text": "finished" } }],
      "population": [{ "count": 1 }] },
    { "component": [{ "code": { "text": "Encounter Status" },
                      "value": { "text": "in-progress" } }],
      "population": [{ "count": 1 }] },
    { "component": [{ "code": { "text": "Gender" },
                      "value": { "text": "male" } }],
      "population": [{ "count": 1 }] }
  ]
}]

MeasureReport stratum — after the fix (two strata, each carrying both components — one per (status, gender) tuple):

"stratifier": [{
  "code": [{ "text": "Encounter Status and Gender" }],
  "stratum": [
    { "component": [
        { "code": { "text": "Encounter Status" }, "value": { "text": "finished" } },
        { "code": { "text": "Gender" },           "value": { "text": "male"     } }
      ],
      "population": [{ "count": 1 }] },
    { "component": [
        { "code": { "text": "Encounter Status" }, "value": { "text": "in-progress" } },
        { "code": { "text": "Gender" },           "value": { "text": "male"        } }
      ],
      "population": [{ "count": 1 }] }
  ]
}]

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