整合求解器活动监控与步长回归证据

同步远端 PNL0003 诊断和大采样网格能力，语义合并活动感知的 60 秒真停滞判定与旧后端 15 分钟兼容兜底。

纳管热路径优化、15 单元运行证据、浏览器与 API 报告，并补充北京时间更新日志和遗留问题。

app/simulation/solvers/algebraic.py

@@ -35,6 +35,12 @@ CAUSAL_EXECUTOR_V2_ENVIRONMENT_VARIABLE = "SIMULATION_CAUSAL_EXECUTOR_V2"
 CAUSAL_COORDINATE_KERNEL_ENVIRONMENT_VARIABLE = (
     "SIMULATION_CAUSAL_COORDINATE_KERNEL"
 )
+CAUSAL_DIRECT_SUM_ASSIGNMENTS_ENVIRONMENT_VARIABLE = (
+    "SIMULATION_CAUSAL_DIRECT_SUM_ASSIGNMENTS"
+)
+CAUSAL_DIRECT_EQUATION_READERS_ENVIRONMENT_VARIABLE = (
+    "SIMULATION_CAUSAL_DIRECT_EQUATION_READERS"
+)
 CAUSAL_FAST_PATH_AUDIT_INTERVAL = 64
 
 
@@ -57,6 +63,20 @@ def _causal_coordinate_kernel_environment_enabled() -> bool:
     return value.strip().lower() not in {"0", "false", "no", "off"}
 
 
+def _causal_direct_sum_assignments_environment_enabled() -> bool:
+    """Return whether exact sum-to-zero targets bypass component tuples."""
+
+    value = os.getenv(CAUSAL_DIRECT_SUM_ASSIGNMENTS_ENVIRONMENT_VARIABLE, "1")
+    return value.strip().lower() not in {"0", "false", "no", "off"}
+
+
+def _causal_direct_equation_readers_environment_enabled() -> bool:
+    """Return whether exact-class scalar residual readers are enabled."""
+
+    value = os.getenv(CAUSAL_DIRECT_EQUATION_READERS_ENVIRONMENT_VARIABLE, "1")
+    return value.strip().lower() not in {"0", "false", "no", "off"}
+
+
 class AlgebraicSolveError(RuntimeError):
     def __init__(
         self,
@@ -127,6 +147,7 @@ class EffortAnchor:
     unknown: AlgebraicUnknown
     evaluate: Callable[[], float]
     equation_id: str
+    causal_evaluate: Callable[[], float] | None = None
 
 
 @dataclass(frozen=True)
@@ -326,6 +347,14 @@ class PressureFlowSolver:
         self.residual_tolerance = residual_tolerance
         self.max_evaluations = max_evaluations
         self.scope_kind = scope_kind
+        self._causal_direct_sum_assignments_environment_enabled = (
+            _causal_direct_sum_assignments_environment_enabled()
+        )
+        self._causal_direct_sum_flow_assignment_count = 0
+        self._causal_direct_equation_readers_environment_enabled = (
+            _causal_direct_equation_readers_environment_enabled()
+        )
+        self._causal_direct_effort_anchor_count = 0
         self.unknowns = self._build_unknowns()
         self._unknowns_by_id = {unknown.id: unknown for unknown in self.unknowns}
         self._unknowns_by_variable = {
@@ -371,6 +400,9 @@ class PressureFlowSolver:
             for item in self._component_equation_plan
             for equation in item.templates
         ) + tuple(item.template for item in self._connection_equation_plan)
+        self._causal_direct_equation_readers = (
+            self._build_causal_direct_equation_readers()
+        )
         self._effort_groups = {
             variable: self._build_effort_equality_groups(variable)
             for variable in ("p", "x", "v")
@@ -418,6 +450,11 @@ class PressureFlowSolver:
             self._causal_fast_path_eligible,
             self._causal_fast_path_fallback_reason,
         ) = self._build_causal_execution_plan()
+        self._causal_direct_effort_anchor_count = sum(
+            assignment.anchor.causal_evaluate is not None
+            for assignments in self._causal_effort_plan_by_variable.values()
+            for assignment in assignments
+        )
         self._causal_fast_path_environment_enabled = (
             _causal_fast_path_environment_enabled()
         )
@@ -599,6 +636,18 @@ class PressureFlowSolver:
             "coordinateKernelFastSolveCount": (
                 self._causal_coordinate_fast_solve_count
             ),
+            "directSumAssignmentsConfigured": (
+                self._causal_direct_sum_assignments_environment_enabled
+            ),
+            "directSumFlowAssignmentCount": (
+                self._causal_direct_sum_flow_assignment_count
+            ),
+            "directEquationReadersConfigured": (
+                self._causal_direct_equation_readers_environment_enabled
+            ),
+            "directEffortAnchorCount": (
+                self._causal_direct_effort_anchor_count
+            ),
             "compiledEffortUnknownCount": (
                 self._causal_compiled_effort_unknown_count
             ),
@@ -850,6 +899,9 @@ class PressureFlowSolver:
             ] = {}
             component_evaluators: dict[int, Callable[[], tuple[float, ...]]] = {}
             for coordinate_index, assignment in indexed_assignments:
+                if assignment.anchor.causal_evaluate is not None:
+                    direct_targets.append((coordinate_index, assignment))
+                    continue
                 equation_index = equation_index_by_id[
                     assignment.anchor.equation_id
                 ]
@@ -934,10 +986,22 @@ class PressureFlowSolver:
             if stage is None:
                 return False
             for coordinate_index, assignment in stage.direct_targets:
-                workspace[coordinate_index] = (
-                    self._read_effort_anchor(assignment)
-                    - assignment.anchor.evaluate()
+                evaluate = (
+                    assignment.anchor.causal_evaluate
+                    if assignment.anchor.causal_evaluate is not None
+                    else assignment.anchor.evaluate
                 )
+                try:
+                    workspace[coordinate_index] = (
+                        self._read_effort_anchor(assignment)
+                        - evaluate()
+                    )
+                except MemoryError:
+                    raise
+                except Exception:
+                    if assignment.anchor.causal_evaluate is None:
+                        raise
+                    return False
             for evaluation in stage.component_evaluations:
                 equation_values = evaluation.evaluate()
                 for target in evaluation.targets:
@@ -975,7 +1039,19 @@ class PressureFlowSolver:
                 return False
             for assignment in assignments:
                 anchor = assignment.anchor
-                target = anchor.unknown.read() - anchor.evaluate()
+                evaluate = (
+                    anchor.causal_evaluate
+                    if anchor.causal_evaluate is not None
+                    else anchor.evaluate
+                )
+                try:
+                    target = anchor.unknown.read() - evaluate()
+                except MemoryError:
+                    raise
+                except Exception:
+                    if anchor.causal_evaluate is None:
+                        raise
+                    return False
                 if not isfinite(target) or (
                     variable == "p" and target <= PRESSURE_LOWER_BOUND_PA
                 ):
@@ -1431,6 +1507,9 @@ class PressureFlowSolver:
                         unknown=unknown,
                         evaluate=self._equation_value_reader(equation),
                         equation_id=equation.id,
+                        causal_evaluate=(
+                            self._causal_direct_equation_readers.get(equation.id)
+                        ),
                     )
                 )
 
@@ -1851,6 +1930,45 @@ class PressureFlowSolver:
 
         return read_component_equation
 
+    def _build_causal_direct_equation_readers(
+        self,
+    ) -> dict[str, Callable[[], float]]:
+        """Compile exact-class scalar residual capabilities, failing closed."""
+
+        if not self._causal_direct_equation_readers_environment_enabled:
+            return {}
+
+        readers: dict[str, Callable[[], float]] = {}
+        for evaluation in self._component_equation_plan:
+            component = evaluation.component
+            # A subclass must repeat the declaration after changing equation
+            # semantics; inherited purity promises are deliberately ignored.
+            declared = type(component).__dict__.get(
+                "pressure_flow_equation_value_readers"
+            )
+            if not callable(declared):
+                continue
+            try:
+                component_readers = declared(component)
+            except MemoryError:
+                raise
+            except Exception:
+                continue
+            if not isinstance(component_readers, Mapping):
+                continue
+            template_ids = frozenset(
+                template.id for template in evaluation.templates
+            )
+            if any(
+                not isinstance(equation_id, str)
+                or equation_id not in template_ids
+                or not callable(reader)
+                for equation_id, reader in component_readers.items()
+            ):
+                continue
+            readers.update(component_readers)
+        return readers
+
     def _connection_flow_target_reader(
         self,
         equation,
@@ -1870,6 +1988,69 @@ class PressureFlowSolver:
             f"Connection flow equation {equation.id} does not contain {unknown.id}."
         )
 
+    def _sum_to_zero_flow_target_reader(
+        self,
+        equation,
+        unknown: AlgebraicUnknown,
+    ) -> Callable[[], float]:
+        """Compile the exact target of a declared flow sum without callbacks."""
+
+        if equation.relation != "sumToZero":
+            raise ValueError(
+                f"Equation {equation.id} is not a sum-to-zero relation."
+            )
+        if len(set(equation.variables)) != len(equation.variables):
+            raise ValueError(
+                f"Equation {equation.id} repeats a sum-to-zero variable."
+            )
+        equation_unknowns: list[AlgebraicUnknown] = []
+        for variable in equation.variables:
+            current = self._unknowns_by_id.get(variable)
+            if current is None or current.role != "flow":
+                raise ValueError(
+                    f"Equation {equation.id} has a non-flow variable."
+                )
+            equation_unknowns.append(current)
+        if not any(current is unknown for current in equation_unknowns):
+            raise ValueError(
+                f"Equation {equation.id} does not contain {unknown.id}."
+            )
+        compiled_unknowns = tuple(equation_unknowns)
+        if len(compiled_unknowns) == 2:
+            first, second = compiled_unknowns
+            return lambda: 0.0 - (first.read() + second.read())
+
+        def target() -> float:
+            # The target unknown is already zeroed by the stage executor.  Keep
+            # its slot in the sum so the floating-point operation order matches
+            # the declared built-in residual, including near cancellation.
+            return 0.0 - sum(current.read() for current in compiled_unknowns)
+
+        return target
+
+    @staticmethod
+    def _component_declares_exact_sum_to_zero_equation(
+        component: object,
+        equation_id: str,
+    ) -> bool:
+        """Accept only an exact concrete-class promise for callback bypass."""
+
+        declared_suffixes = type(component).__dict__.get(
+            "PRESSURE_FLOW_EXACT_SUM_TO_ZERO_EQUATION_SUFFIXES"
+        )
+        if not isinstance(declared_suffixes, frozenset) or any(
+            not isinstance(suffix, str) or not suffix or ":" in suffix
+            for suffix in declared_suffixes
+        ):
+            return False
+        component_name = getattr(component, "name", None)
+        if not isinstance(component_name, str):
+            return False
+        return any(
+            equation_id == f"{component_name}:{suffix}"
+            for suffix in declared_suffixes
+        )
+
     def _pressure_flow_equation_values(self) -> tuple[float, ...]:
         """Evaluate live equation values through the compiled topology."""
 
@@ -1918,6 +2099,29 @@ class PressureFlowSolver:
 
         evaluation = self._component_equation_plans_by_id[equation.owner_id]
         component = evaluation.component
+        if (
+            self._causal_direct_sum_assignments_environment_enabled
+            and equation.relation == "sumToZero"
+            and self._component_declares_exact_sum_to_zero_equation(
+                component,
+                equation.id,
+            )
+        ):
+            try:
+                evaluate = self._sum_to_zero_flow_target_reader(
+                    equation,
+                    unknown,
+                )
+            except ValueError:
+                pass
+            else:
+                self._causal_direct_sum_flow_assignment_count += 1
+                return ExplicitFlowAssignment(
+                    equation_id=equation.id,
+                    unknown=unknown,
+                    evaluate=evaluate,
+                )
+
         equations = evaluation.templates
         equation_ids = tuple(current.id for current in equations)
         try: