docs: policy-safe README intro + Before-you-ship section

[fonkamloic]

Summary

• Rewrote the intro paragraph to describe outcomes (ship fixes between releases, signed patches, auto crash recovery) instead of implying a store-review bypass.
• Added a "Before you ship" section pointing developers to Google Play's Device and Network Abuse policy and App Store Review Guideline 3.3.2, and noting distribution decisions are the developer's own.
• Documented disableOnPlayStoreInstalls in the section and in the CodePushConfig parameter table.
• Clarified iOS live patching applies to bytecode data modules.

README ships with the next release; no publish in this PR.

[claude]

🔴 Critical

None

🟠 Medium

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🟡 Low

None

🟢 Positives

Responsible messaging rewrite: The intro paragraph shift from "push updates...without going through the app store review process" to "ship Dart fixes...with signed patches and automatic crash recovery" is significantly more accurate and responsible. It frames code push as a capability (rapid hotfixes) rather than implying a store-review bypass.

Strong compliance guidance: The new "Before you ship" section is well-designed:

• Correctly clarifies that only Dart code is updated, never native code/resources/permissions
• Points developers directly to the actual store policies (Google Play Device and Network Abuse, App Store Review Guideline 3.3.2)
• Properly places responsibility on the developer
• Offers disableOnPlayStoreInstalls as a compliance option for Play Store concerns

Technical accuracy: All descriptions align with the implementation:

• disableOnPlayStoreInstalls parameter correctly documented (default false)
• Behavior accurately described (disables OTA on Play Store installs; other channels unaffected)
• "bytecode data modules load without restarting the app" for iOS is precise
• Crash protection and signature verification sections are thorough
• Platform behavior table is complete and accurate

Implementation consistency: Verified that the code path (lines 286–315 in code_push.dart) correctly implements the described behavior: early return to skip the entire update flow, patch removal, and telemetry reporting when disableOnPlayStoreInstalls is set and a Play Store install is detected.