Vendor the ASN.1 modules the codecs are verified against; untrack IDE churn

asn1/
Three tests assert exact bytes - CamEncodeGoldenTest, DenmAirReceiveTest and
SpatemUperCodecTest - and their expected values came from asn1tools compiled
against ETSI modules that existed only as an untracked working copy on one
machine. A golden-byte fixture nobody else can regenerate is a fixture nobody
can safely touch, so the modules are now in the repo.

Only the seven .asn files those tests need are copied, 576 KB of a 4.2 MB
checkout; the upstream Rust parser is not used by this project at all. Verified
sufficient in isolation: copied into an empty directory, all three specs compile
and reproduce the committed golden CAM bytes byte-identically.

Source is consider it GmbH's C-ITS-Parser (github.com/consider-it/C-ITS-Parser)
at f457426, MIT licensed - LICENSE is retained alongside as that requires. The
schemas themselves are ETSI's standard definitions; upstream's contribution is
assembling them into a compilable set. asn1/README.md records the provenance,
which module pairs with which message, and the rule that matters: never
regenerate a golden fixture from this project's own encoder, because sharing a
mistake between encoder and decoder is exactly the failure these files exist to
catch.

Doc references in the codecs and tests now point at asn1/ instead of the
untracked checkout, and C-ITS-Parser/ is gitignored so the working copy beside
the project is never picked up.

Untracked local state
- .idea/deploymentTargetSelector.xml rewrites itself on every deploy, so it has
  been showing as modified in essentially every commit. Along with
  deviceManager.xml, appInsightsSettings.xml and studiobot.xml it is per-machine
  state, not project configuration.
- obu-firmware/sdkconfig.old is ESP-IDF build output - it is the previous
  sdkconfig, rewritten on every build. sdkconfig.defaults remains tracked, since
  that is the configuration actually chosen.

All five stay on disk; only the tracking is removed. Also ignores
.claude/settings.local.json, which is per-machine, while leaving the skills
beside it committable as project knowledge.

asn1/cam_1_4_1.asn

@@ -0,0 +1,132 @@
+CAM-PDU-Descriptions {
+itu-t (0) identified-organization (4) etsi (0) itsDomain (5) wg1 (1) en (302637) cam (2) version (2) 
+}
+
+DEFINITIONS AUTOMATIC TAGS ::=
+
+BEGIN
+
+IMPORTS 
+ItsPduHeader, CauseCode, ReferencePosition, AccelerationControl, Curvature, CurvatureCalculationMode, Heading, LanePosition, EmergencyPriority, EmbarkationStatus, Speed, DriveDirection, LongitudinalAcceleration, LateralAcceleration, VerticalAcceleration, StationType, ExteriorLights, DangerousGoodsBasic, SpecialTransportType, LightBarSirenInUse, VehicleRole, VehicleLength, VehicleWidth, PathHistory, RoadworksSubCauseCode, ClosedLanes, TrafficRule, SpeedLimit, SteeringWheelAngle, PerformanceClass, YawRate, ProtectedCommunicationZone, PtActivation, Latitude, Longitude, ProtectedCommunicationZonesRSU, CenDsrcTollingZone FROM ITS-Container {
+itu-t (0) identified-organization (4) etsi (0) itsDomain (5) wg1 (1) ts (102894) cdd (2) version (2) 
+};
+
+
+--	The root data frame for cooperative awareness messages
+
+CAM ::= SEQUENCE {
+	header ItsPduHeader,
+	cam CoopAwareness
+}
+
+CoopAwareness ::= SEQUENCE {
+	generationDeltaTime GenerationDeltaTime,
+	camParameters CamParameters
+}
+
+CamParameters ::= SEQUENCE {
+	basicContainer BasicContainer,
+	highFrequencyContainer HighFrequencyContainer,
+	lowFrequencyContainer LowFrequencyContainer OPTIONAL,
+	specialVehicleContainer SpecialVehicleContainer OPTIONAL,
+	...
+}
+
+HighFrequencyContainer ::= CHOICE {
+	basicVehicleContainerHighFrequency BasicVehicleContainerHighFrequency,
+	rsuContainerHighFrequency RSUContainerHighFrequency,
+	...
+}
+
+ LowFrequencyContainer ::= CHOICE {
+  basicVehicleContainerLowFrequency BasicVehicleContainerLowFrequency,
+	...
+}
+
+SpecialVehicleContainer ::= CHOICE {
+	publicTransportContainer PublicTransportContainer,
+	specialTransportContainer SpecialTransportContainer,
+	dangerousGoodsContainer DangerousGoodsContainer,
+	roadWorksContainerBasic RoadWorksContainerBasic,
+	rescueContainer RescueContainer,
+	emergencyContainer EmergencyContainer,
+	safetyCarContainer SafetyCarContainer,
+	...
+}
+
+BasicContainer ::= SEQUENCE {
+	stationType StationType,
+	referencePosition ReferencePosition,
+	...
+}
+
+BasicVehicleContainerHighFrequency ::= SEQUENCE {
+	heading Heading,
+	speed Speed,
+	driveDirection DriveDirection,
+	vehicleLength VehicleLength,
+	vehicleWidth VehicleWidth,
+	longitudinalAcceleration LongitudinalAcceleration,
+	curvature Curvature,
+	curvatureCalculationMode CurvatureCalculationMode,
+	yawRate YawRate,
+	accelerationControl AccelerationControl OPTIONAL,
+	lanePosition LanePosition OPTIONAL,
+	steeringWheelAngle SteeringWheelAngle OPTIONAL,
+	lateralAcceleration LateralAcceleration OPTIONAL,
+	verticalAcceleration VerticalAcceleration OPTIONAL,
+	performanceClass PerformanceClass OPTIONAL,
+	cenDsrcTollingZone CenDsrcTollingZone OPTIONAL
+}
+
+BasicVehicleContainerLowFrequency  ::= SEQUENCE {
+	vehicleRole VehicleRole,
+	exteriorLights ExteriorLights,
+	pathHistory PathHistory
+}
+
+PublicTransportContainer ::= SEQUENCE {
+	embarkationStatus EmbarkationStatus,
+	ptActivation PtActivation OPTIONAL
+}
+
+SpecialTransportContainer ::= SEQUENCE {
+	specialTransportType SpecialTransportType,
+	lightBarSirenInUse LightBarSirenInUse
+}
+
+ DangerousGoodsContainer ::= SEQUENCE {
+  dangerousGoodsBasic DangerousGoodsBasic
+ }
+ 
+ RoadWorksContainerBasic ::= SEQUENCE {
+  roadworksSubCauseCode RoadworksSubCauseCode OPTIONAL,
+  lightBarSirenInUse LightBarSirenInUse,
+  closedLanes ClosedLanes OPTIONAL
+ }
+
+RescueContainer ::= SEQUENCE {
+	lightBarSirenInUse LightBarSirenInUse
+}
+
+EmergencyContainer ::= SEQUENCE {
+	lightBarSirenInUse LightBarSirenInUse,
+	incidentIndication CauseCode OPTIONAL,
+	emergencyPriority EmergencyPriority OPTIONAL
+}
+
+SafetyCarContainer ::= SEQUENCE {
+	lightBarSirenInUse LightBarSirenInUse,
+	incidentIndication CauseCode OPTIONAL,
+	trafficRule TrafficRule OPTIONAL,
+	speedLimit SpeedLimit OPTIONAL
+}
+
+RSUContainerHighFrequency ::= SEQUENCE {
+	protectedCommunicationZonesRSU ProtectedCommunicationZonesRSU OPTIONAL,
+	...
+}
+
+GenerationDeltaTime ::= INTEGER { oneMilliSec(1) } (0..65535)
+
+END