feat: shell execution correctness + artifact_field_equals condition

- Add  field to ProcessResultArtifact ("success"/"failed")
- Materialize ToolResult.Failure as a failed ProcessResult artifact
  in the orchestrator, with artifact lifecycle events emitted
- Non-recoverable ToolResult.Failure now fails the stage ("FATAL:")
  instead of being silently fed back as LLM context
- Fix enterStage to return Continue on non-retryable failures,
  enabling back-edge transitions (fix/retry loops)
- Add ArtifactFieldEquals transition condition with flat and
  nested dot-notation field access + FieldOperator enum
  (eq, neq, gt, gte, lt, lte)
- Wire artifact_field_equals through ConditionFactory and
  TomlWorkflowLoader (condition_field, condition_operator)
- Cache ProcessResult artifact content for evaluation context
- Add 16 tests covering all condition operators and error cases
- DefaultTransitionResolver catches condition evaluation errors
  and returns Blocked instead of crashing

infrastructure/workflow/src/main/kotlin/com/correx/infrastructure/workflow/ConditionFactory.kt

@@ -5,8 +5,10 @@ import com.correx.core.transitions.conditions.AllOf
 import com.correx.core.transitions.conditions.AlwaysTrue
 import com.correx.core.transitions.conditions.AnyOf
 import com.correx.core.transitions.conditions.ArtifactAbsent
+import com.correx.core.transitions.conditions.ArtifactFieldEquals
 import com.correx.core.transitions.conditions.ArtifactPresent
 import com.correx.core.transitions.conditions.ArtifactValidated
+import com.correx.core.transitions.conditions.FieldOperator
 import com.correx.core.transitions.conditions.Not
 import com.correx.core.transitions.conditions.VariableEquals
 import com.correx.core.transitions.graph.TransitionCondition
@@ -17,6 +19,7 @@ fun ConditionSpec.toCondition(): TransitionCondition = when (type) {
     "artifact_absent" -> buildArtifactAbsent()
     "artifact_validated" -> buildArtifactValidated()
     "variable_equals" -> buildVariableEquals()
+    "artifact_field_equals" -> buildArtifactFieldEquals()
     "all_of" -> AllOf(conditions.map { it.toCondition() })
     "any_of" -> AnyOf(conditions.map { it.toCondition() })
     "not" -> Not((condition ?: error("condition required for not")).toCondition())
@@ -37,3 +40,11 @@ private fun ConditionSpec.buildVariableEquals() =
         key ?: error("key required for variable_equals"),
         value ?: error("value required for variable_equals"),
     )
+
+private fun ConditionSpec.buildArtifactFieldEquals() =
+    ArtifactFieldEquals(
+        artifactId = ArtifactId(artifactId ?: error("artifact_id required for artifact_field_equals")),
+        field = field ?: error("field required for artifact_field_equals"),
+        value = value ?: error("value required for artifact_field_equals"),
+        operator = operator?.let { FieldOperator.fromString(it) } ?: FieldOperator.EQ,
+    )

infrastructure/workflow/src/main/kotlin/com/correx/infrastructure/workflow/ConditionSpec.kt

@@ -5,6 +5,8 @@ data class ConditionSpec(
     val artifactId: String? = null,
     val key: String? = null,
     val value: String? = null,
+    val field: String? = null,
+    val operator: String? = null,
     val conditions: List<ConditionSpec> = emptyList(),
     val condition: ConditionSpec? = null,
 )

infrastructure/workflow/src/main/kotlin/com/correx/infrastructure/workflow/TomlWorkflowLoader.kt

@@ -49,6 +49,8 @@ private data class TransitionSection(
     @param:JsonProperty("condition_artifact_id") val conditionArtifactId: String? = null,
     @param:JsonProperty("condition_key") val conditionKey: String? = null,
     @param:JsonProperty("condition_value") val conditionValue: String? = null,
+    @param:JsonProperty("condition_field") val conditionField: String? = null,
+    @param:JsonProperty("condition_operator") val conditionOperator: String? = null,
 )
 
 private const val TERMINAL = "done"
@@ -112,6 +114,8 @@ class TomlWorkflowLoader(
                     artifactId = t.conditionArtifactId,
                     key = t.conditionKey,
                     value = t.conditionValue,
+                    field = t.conditionField,
+                    operator = t.conditionOperator,
                 ).toCondition(),
             )
         }.toSet()