Complete Chinese translations

[caydyan]

Summary

• completes remaining Chinese values-zh strings for onboarding, chat attachments, and tribe badges
• adds the missing Chinese resource file for the Firebase notification channel string
• keeps product/channel names like Sphinx, GitHub, Lightning Network, and FCM unchanged

Fixes #460.

Validation

• XML parsed all changed values-zh/strings.xml files with Python xml.etree.ElementTree
• Compared changed Chinese resources against their default values/strings.xml files; no missing string keys in the touched resource sets
• git diff --check
• JAVA_HOME=/opt/homebrew/opt/openjdk@17/libexec/openjdk.jdk/Contents/Home ANDROID_HOME=/tmp/codex-android-sdk-real ANDROID_SDK_ROOT=/tmp/codex-android-sdk-real ./gradlew :sphinx:activity:main:activitymain:mergeDebugResources --no-daemon --stacktrace

Bounty payout address: bc1qev5ant33v5y89qqjvcf4mh9hlax5svqf5xd7gc

[caydyan]

Current-head validation rerun on 0a69877ec513c28ba76ce6dfe4e555f365658eb2:

• Structured XML/key coverage passed for all 5 touched values-zh/strings.xml files against their base values/strings.xml files.
• git diff --check origin/master...HEAD passed.
• ./gradlew :sphinx:screens-detail:chat-detail:tribe-detail:mergeDebugResources :sphinx:screens:chats:chat-common:chat-common:mergeDebugResources :sphinx:screens:onboard:onboard-connect:mergeDebugResources :sphinx:screens:onboard:onboard-resources:mergeDebugResources passed.

I also attempted ./gradlew :sphinx:service:features:notifications:feature-service-notification-firebase:mergeDebugResources; it reaches processDebugGoogleServices and is blocked locally because this checkout does not include google-services.json. No Chinese resource XML/key issue was reported before that environment/config gate.

Local worktree is clean after the rerun.