[PANA-5681] Preparation for Heatmaps cross-platform integration

[jonathanmos]

What does this PR do?

Reorganise heatmap types into correct packages

Public declarations (CrossPlatformHeatmapActionData, HeatmapIdentifierRegistryProvider, heatmapViewKey) are moved out of com.datadog.android.internal.heatmaps, since public types must not live in a package named internal. isValidTapTarget was moved out of heatmaps since it is a general util.

HeatmapActionData is split into two distinct types:

NativeHeatmapActionData — carries a viewKey (a composite identity hash of the tapped View and its parent), used to look up a pre-computed identifier from the HeatmapIdentifierRegistry that Session Replay populated during its last traversal.
CrossPlatformHeatmapActionData — carries an elementPath (a list of string path segments) and viewUrl, from which the identifier is computed on demand at action-send time via HeatmapIdentifier.create().
HeatmapActionResolver and NativeHeatmapActionData are also moved from rum.internal.domain.scope (where they are not scope concepts) to the dedicated rum.internal.heatmaps package.

Add cross-platform heatmap tap action support

Exposes two new methods on _RumInternalProxy for cross-platform SDKs (React Native, etc.):

getCurrentViewUrl() — returns the URL of the currently active RUM view. Cross-platform SDKs must call this at tap time and use the result as both the screen name for Session Replay wireframe identifier computation and the viewUrl field of CrossPlatformHeatmapActionData.
addActionWithHeatmap() — records a tap action with heatmap data attached. The Android SDK validates that the view URL captured at tap time still matches the active view at action-send time, dropping the heatmap data (with a developer-facing warning) if navigation has occurred in between.

Motivation

Heatmaps on Android currently only work with native gesture tracking. This PR lays the foundation for cross-platform SDKs to emit heatmap-tagged tap actions, enabling heatmap features in React Native and future cross-platform targets.

Additional Notes

getCurrentViewUrl() reads from a volatile cached field updated after each RUM event, making it safe to call from the UI thread without blocking on the RUM executor.
The view URL mismatch guard in HeatmapActionResolver.CrossPlatform handles the inherent race between a tap on screen A and a navigation to screen B: if the view has changed by the time the action is processed, the heatmap data is dropped rather than attributed to the wrong screen.
Identifier computation for cross-platform actions uses the same HeatmapIdentifier.create() path as Session Replay, ensuring the resulting permanentId matches the wireframe identifier SR computed for the same element.

Review checklist (to be filled by reviewers)

• Feature or bugfix MUST have appropriate tests (unit, integration, e2e)
• Make sure you discussed the feature or bugfix with the maintaining team in an Issue
• Make sure each commit and the PR mention the Issue number (cf the CONTRIBUTING doc)

[codecov-commenter]

Codecov Report

❌ Patch coverage is 71.56863% with 29 lines in your changes missing coverage. Please review.
✅ Project coverage is 72.22%. Comparing base (aea05eb) to head (6784792).
⚠️ Report is 2 commits behind head on feature/heatmaps.

Files with missing lines	Patch %	Lines
...oid/rum/internal/heatmaps/HeatmapActionResolver.kt	79.07%	7 Missing and 2 partials ⚠️
...android/heatmaps/CrossPlatformHeatmapActionData.kt	0.00%	7 Missing ⚠️
...dog/android/internal/heatmaps/HeatmapIdentifier.kt	45.45%	6 Missing ⚠️
...ndroid/rum/internal/domain/scope/RumActionScope.kt	50.00%	4 Missing and 2 partials ⚠️
...lay/internal/recorder/HeatmapIdentifierResolver.kt	0.00%	1 Missing ⚠️

Additional details and impacted files

@@                 Coverage Diff                  @@
##           feature/heatmaps    #3549      +/-   ##
====================================================
+ Coverage             72.19%   72.22%   +0.03%     
====================================================
  Files                   970      972       +2     
  Lines                 35668    35751      +83     
  Branches               5937     5944       +7     
====================================================
+ Hits                  25748    25820      +72     
- Misses                 8289     8312      +23     
+ Partials               1631     1619      -12     

Files with missing lines	Coverage Δ
...ava/com/datadog/android/heatmaps/HeatmapViewKey.kt	100.00% <ø> (ø)
...m/datadog/android/internal/utils/TapTargetUtils.kt	100.00% <ø> (ø)
...rum/src/main/kotlin/com/datadog/android/rum/Rum.kt	86.42% <100.00%> (+0.17%)	⬆️
...otlin/com/datadog/android/rum/_RumInternalProxy.kt	68.00% <100.00%> (+2.78%)	⬆️
...lin/com/datadog/android/rum/internal/RumFeature.kt	92.81% <ø> (-0.23%)	⬇️
...g/android/rum/internal/domain/scope/RumRawEvent.kt	100.00% <100.00%> (ø)
...d/rum/internal/heatmaps/NativeHeatmapActionData.kt	100.00% <100.00%> (ø)
...entation/gestures/AndroidActionTrackingStrategy.kt	94.44% <ø> (ø)
...ernal/instrumentation/gestures/GesturesListener.kt	93.71% <100.00%> (ø)
.../android/rum/internal/monitor/DatadogRumMonitor.kt	87.87% <100.00%> (+0.69%)	⬆️
... and 7 more

... and 41 files with indirect coverage changes

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[chatgpt-codex-connector]

Return a fresh view URL for queued view changes

When a cross-platform SDK calls getCurrentViewUrl() immediately after a startView/navigation event, that view change has only been enqueued through handleEvent/withWriteContext; cachedViewUrl is not updated until the RUM executor later reaches updateCachedViewUrl. This can return the previous URL or null, and the subsequent addActionWithHeatmap() is later resolved against the newly processed view, causing the mismatch guard to drop otherwise valid heatmap data. Consider updating this cache when queuing view changes or exposing a synchronous read that accounts for pending events.

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[jonathanmos]

The race window here is real but narrow, and the viewurl check already handles it. The purpose of viewUrl is to ensure the hash is computed with the same URL string Session Replay is using — so if cachedViewUrl is stale and we let the action through, we'd produce a hash that would risk a misleading correlation. The guard dropping the data in that case isn't data loss, it's the right outcome. Taps that land at the exact moment of navigation are inherently ambiguous. I'll add a comment to getCurrentViewUrl() explaining this, but I don't think a code change is warranted.