fix(android): ship R8 keep rules for DocuSign's esign models

[IronTony]

Ships R8 keep rules with the module, so an app that turns on minification keeps DocuSign login and captive signing working without adding rules of its own. Released as 2.0.1.

Why

• DocuSign's androidsdk-2.1.7.aar ships consumer rules that keep com.docusign.androidsdk.** only.
• The Gson models live in sdk-esign-api-2.1.7.jar (com.docusign.esign.model, 580 classes), a plain JAR with no META-INF/proguard rules. The SDK names them only in generic signatures, so R8 finds no use and removes all of them. Login and captive signing then fail at runtime, and nothing crashes at launch.
• The module already pins the DocuSign SDK version and the sdk-pdf SHA, so the rule sits next to those pins. Consuming apps get it through consumerProguardFiles with no setup.

Changes

• android/consumer-rules.pro (new): keeps com.docusign.esign.model.** { *; }. Keeping all of com.docusign.esign.** fails R8 on the missing org.apache.oltu classes the esign client references, so the rule covers the models only. It also has -keepnames class expo.modules.docusign.**, so DocuSignError.native.domain stays readable in an obfuscated build.
• android/build.gradle: consumerProguardFiles 'consumer-rules.pro' in defaultConfig.
• package.json, package-lock.json: 2.0.1.
• CHANGELOG.md: a 2.0.1 Fixes entry.
• README.md: a "Minified release builds (R8)" section after the Glide workaround.

The module's own Kotlin needs no rules. Error codes are explicit, expo-modules-core's consumer rules keep the Records, the recipient-view request uses JSONObject, and the JS network classifier matches java.net.* names, which R8 never renames.

Verification

• Lint, build and all 101 Jest tests pass. npm pack includes android/consumer-rules.pro.
• An Expo SDK 57 app with enableMinifyInReleaseBuilds, built with ./gradlew :app:assembleRelease (arm64):

	2.0.0	2.0.1
Rule in merged configuration.txt	no	yes
com.docusign.esign.model classes in dex	0 of 580	580 of 580
ViewUrl.url	gone	present
APK	24.4 MB	25.1 MB

• Pre-push review returned Ship on 17babf5 with no blocking findings. Its one follow-up is the device run below, which would back the README's claim that apps need no DocuSign keep rules of their own.
• Not run: login and captive signing on a device with a minified build. The dex check shows the classes and fields survive. It does not exercise Gson at runtime.

Notes

• Running ./gradlew assembleRelease from the root of a consuming app fails in :react-native-docusign:bundleReleaseAar, because AGP rejects the local sdk-pdf .aar when it bundles a library AAR. This predates 2.0.1. :app:assembleRelease and EAS builds are unaffected.
• The 0.6 MB is the cost of keeping the whole model package. Narrowing it to the models the SDK references today would need re-checking on every SDK bump.