fix: retain completed observations when later analysis steps fail

docs/android-analysis.md

@@ -118,6 +118,12 @@ selected overload. Native/abstract methods with no decompiled body report
   responses remain in Evidence. Source revision is populated only for bytes
   matching the audited release JAR.
 
+If a later step fails, the error's `details.partial_observation` retains the
+selected and resolved APK paths, digest, observed provider identity and versions,
+and each upstream request and reply collected before the failure. Failed replies
+remain available even when their payload cannot be interpreted. Cancellation
+also stops target hashing before provider admission.
+
 These operations do not execute the APK or provide split APK/AAB handling,
 signature validation, full resource-table semantics, native-library analysis or
 Android runtime capture. Existing artifact inventory/extraction tools can supply