Feat: Complete adaptive geodesic tracing with DP54

Add error-controlled DP5(4) integration and trusted first-crossing localization, including non-monotonic energy thresholds and representable-time stepping.

Preserve adaptive state and independent step/time retry grants across RayPool, refinement and movie scheduling. Expose numerical controls, record actual persistent-sample costs, and add v3 lens-map provenance with legacy v2 RK4 import.

Use DP54 by default and select an 8M Schwarzschild maximum step from bounded scans and a two-run 4K comparison. Retain the conservative minimum-step guard and document critical-ray and backend capability limits. Archive self-contained benchmark inputs and raw output; keep fixed RK4 HDR references explicit.

Validation: make -B -j4 BUILD_TYPE=Debug test passed; explicit RK4 HDR references have zero differences. Bounded convergence checks, benchmark reproduction, Release build and focused reviews passed. No numerical-relativity backend is added.

Makefile

@@ -106,6 +106,7 @@ endif
 # built for a different backend.
 TEST_OUT_DIR := $(OBJECT_DIR)/$(HDR_BUILD_TAG)
 TEST_TARGET := $(TEST_OUT_DIR)/test_geodesic
+ADAPTIVE_GEODESIC_TEST_TARGET := $(TEST_OUT_DIR)/test_geodesic_adaptive
 ASYMPTOTIC_TEST_TARGET := $(TEST_OUT_DIR)/test_asymptotic
 ASYMPTOTIC_SCHWARZSCHILD_TEST_TARGET := $(TEST_OUT_DIR)/test_asymptotic_schwarzschild
 TERMINATION_ORACLE_TEST_TARGET := $(TEST_OUT_DIR)/test_termination_oracle
@@ -207,6 +208,12 @@ $(TEST_OUT_DIR): | $(BUILD_DIR)
 $(TEST_TARGET): tests/test_geodesic.c $(CORE_MINKOWSKI_SOURCES) $(CPU_FFTW_SOURCES) | $(TEST_OUT_DIR)
 	$(CC) $(CPPFLAGS) $(BUILD_CPPFLAGS) $(CFLAGS) $(BUILD_CFLAGS) $(OPENMP_FLAGS) -Isrc $^ $(LDLIBS) -o $@
 
+# Explicit adaptive DP5(4) core and RayPool regression.  The test textually
+# includes both analytic providers (renaming spacetime_create_default), so the
+# link line deliberately omits src/spacetime_{minkowski,schwarzschild}.c.
+$(ADAPTIVE_GEODESIC_TEST_TARGET): tests/test_geodesic_adaptive.c $(COMMON_SOURCES) $(CPU_FFTW_SOURCES) | $(TEST_OUT_DIR)
+	$(CC) $(CPPFLAGS) $(BUILD_CPPFLAGS) $(CFLAGS) $(BUILD_CFLAGS) $(OPENMP_FLAGS) -DGEODESIC_EVENT_TESTING -Isrc $^ $(LDLIBS) -o $@
+
 $(ASYMPTOTIC_TEST_TARGET): tests/test_asymptotic.c $(CORE_MINKOWSKI_SOURCES) $(CPU_FFTW_SOURCES) | $(TEST_OUT_DIR)
 	$(CC) $(CPPFLAGS) $(BUILD_CPPFLAGS) $(CFLAGS) $(BUILD_CFLAGS) $(OPENMP_FLAGS) -Isrc $^ $(LDLIBS) -o $@
 
@@ -273,10 +280,11 @@ FAST_PSF_FFTW_TEST_DEP :=
 FAST_PSF_FFTW_TEST_RUN :=
 endif
 
-test: $(CAMERA_TEST_TARGETS) $(TEST_TARGET) $(ASYMPTOTIC_TEST_TARGET) $(ASYMPTOTIC_SCHWARZSCHILD_TEST_TARGET) $(TERMINATION_ORACLE_TEST_TARGET) $(FRAME_TEST_TARGET) $(SCHWARZSCHILD_TEST_TARGET) $(ALCUBIERRE_TEST_TARGET) $(OBSERVER_TRACK_TEST_TARGET) $(CATALOG_PREFETCH_TEST_TARGET) $(FAST_PSF_FFTW_TEST_DEP) $(TONE_MAP_TEST_TARGET) $(MOVIE_OUTPUT_TEST_TARGET) $(SENSOR_BLOOM_TEST_TARGET)
+test: $(CAMERA_TEST_TARGETS) $(TEST_TARGET) $(ADAPTIVE_GEODESIC_TEST_TARGET) $(ASYMPTOTIC_TEST_TARGET) $(ASYMPTOTIC_SCHWARZSCHILD_TEST_TARGET) $(TERMINATION_ORACLE_TEST_TARGET) $(FRAME_TEST_TARGET) $(SCHWARZSCHILD_TEST_TARGET) $(ALCUBIERRE_TEST_TARGET) $(OBSERVER_TRACK_TEST_TARGET) $(CATALOG_PREFETCH_TEST_TARGET) $(FAST_PSF_FFTW_TEST_DEP) $(TONE_MAP_TEST_TARGET) $(MOVIE_OUTPUT_TEST_TARGET) $(SENSOR_BLOOM_TEST_TARGET)
 	$(TEST_OUT_DIR)/test_observer_minkowski
 	$(TEST_OUT_DIR)/test_observer_schwarzschild
 	$(TEST_TARGET)
+	$(ADAPTIVE_GEODESIC_TEST_TARGET)
 	$(ASYMPTOTIC_TEST_TARGET)
 	$(ASYMPTOTIC_SCHWARZSCHILD_TEST_TARGET)
 	$(TERMINATION_ORACLE_TEST_TARGET)
@@ -290,6 +298,7 @@ test: $(CAMERA_TEST_TARGETS) $(TEST_TARGET) $(ASYMPTOTIC_TEST_TARGET) $(ASYMPTOT
 	$(MOVIE_OUTPUT_TEST_TARGET)
 	$(SENSOR_BLOOM_TEST_TARGET)
 	python3 tests/test_camera_cli.py $(BUILD_DIR) $(TEST_OUT_DIR)
+	python3 tests/test_adaptive_cli.py $(BUILD_DIR) $(TEST_OUT_DIR)
 
 tone-map-test: $(TONE_MAP_TEST_TARGET)
 	$(TONE_MAP_TEST_TARGET)