docs(android): document v1 ANR watchdog limitations on Android 10 and below

[InterstellarStella]

Summary

Documents the known structural limitations of the v1 ANR Watchdog used on
Android 10 and below, where genuine ANRs (including those that produce a
system "App isn't responding" dialog) can be silently dropped by the SDK due
to the ActivityManager.getProcessesInErrorState() gate in
ANRWatchDog.isProcessNotResponding(). Also clarifies that ANR rate
calculated from these devices is a lower bound, and adds a short
troubleshooting note for users investigating "missing" ANRs.

Tracking issue: getsentry/sentry-java#5332

Motivation

Multiple users report ANRs that appear in Google Play Console / system ANR
dialog but never reach Sentry on Android 10. Today the docs only mention
that v1 has "false positives", with no acknowledgement of false negatives or
guidance on how to confirm the limitation. This addition gives users a clear
explanation, a way to self-diagnose, and sets correct expectations for ANR
rate dashboards.

Changes

• Adds a "Known limitations on Android 10 and below" subsection under
  Watchdog (v1).
• Adds a clarifying <Note> to the ANR Rate section explaining that v1
  rates can under-report.
• Adds a small troubleshooting tip pointing users at debug logs.

No content was removed; existing copy and configuration examples are
preserved.

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Project	Deployment	Actions	Updated (UTC)
sentry-docs	Ready	Preview, Comment	Apr 27, 2026 0:41am

1 Skipped Deployment

Project	Deployment	Actions	Updated (UTC)
develop-docs	Ignored		Apr 27, 2026 0:41am

[sentry]

Bug: The troubleshooting advice for missing ANR events may be logically flawed, potentially misguiding developers on the cause of a missing event.
_{Severity: LOW}

Suggested Fix

Verify the order of operations in the sentry-java SDK to confirm if the "ANR triggered" log is generated before or after the isProcessNotResponding() gate check. Update the documentation to accurately reflect the SDK's behavior and prevent confusion during troubleshooting.

Prompt for AI Agent

Review the code at the location below. A potential bug has been identified by an AI
agent. Verify if this is a real issue. If it is, propose a fix; if not, explain why it's
not valid.

Location: docs/platforms/android/configuration/app-not-respond.mdx#L71-L72

Potential issue: The troubleshooting documentation for Android ANR (Application Not
Responding) events may be logically flawed. It states that if the log message `"ANR
triggered with message: Application Not Responding for at least N ms."` is absent, it
means the SDK suppressed the event after checking
`ActivityManager.getProcessesInErrorState()`. However, the log is likely generated
*before* this check. If this is the case, the absence of the log would indicate the hang
was never detected in the first place, not that it was suppressed. This could misguide
developers into investigating the wrong root cause for a missing ANR event.

_{Did we get this right? 👍 / 👎 to inform future reviews.}