fix(gestures): Replace GestureDetectorCompat with lightweight detector to fix ANR (#5138)

* fix(android): Replace GestureDetectorCompat with lightweight SentryGestureDetector to fix ANR

GestureDetectorCompat internally uses Handler.sendMessage/removeMessages which
acquires a synchronized lock on the main thread MessageQueue, plus
recordGestureClassification triggers IPC calls. This caused ANRs under load
(SDK-CRASHES-JAVA-596, 175K+ occurrences).

Replace with a minimal custom detector that only detects click, scroll, and
fling without any Handler scheduling, MessageQueue contention, or IPC overhead.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* test(android): Add unit tests for SentryGestureDetector

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* changelog

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* fix(gestures): Clear VelocityTracker on ACTION_DOWN to prevent stale velocity data

Matches GestureDetector behavior: if consecutive ACTION_DOWN events
arrive without an intervening ACTION_UP/ACTION_CANCEL, stale motion
data could bleed into fling detection.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* fix(gestures): Remove stale GestureDetectorCompat class availability check

UserInteractionIntegration gated itself on GestureDetectorCompat being
available via classloader check, but SentryGestureDetector only uses
Android SDK classes. Remove the check so the integration works without
androidx.core. Also remove the stale proguard -keep rule.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* Move changelog entry

* ref(gestures): Simplify SentryGestureDetector resource lifecycle

Keep VelocityTracker alive across gesture cycles instead of
obtain/recycle churn on every gesture. Add release() method called
from SentryWindowCallback.stopTracking() to prevent native resource
leaks when activity is destroyed mid-gesture. Also fix broken Javadoc
@link to removed dependency, change onTouchEvent return to void, and
remove redundant null check.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* fix(gestures): Handle multi-touch to prevent spurious tap detection

When a second finger touches the screen (ACTION_POINTER_DOWN), cancel
tap detection by setting isInTapRegion to false. Previously, pinch-to-zoom
gestures where the first finger stayed still would incorrectly trigger
onSingleTapUp, producing false click breadcrumbs.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* chore: Register btrace-perfetto skill in agents.toml

Add local btrace-perfetto skill for capturing and comparing Perfetto
traces on Android devices using btrace 3.0.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* chore: Add btrace-perfetto skill for Perfetto trace capture

Workflow skill that automates capturing and comparing Perfetto traces
using btrace 3.0 on Android devices. Includes a Perfetto UI viewer
template with SQL query deep-linking via postMessage API.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* chore: Update btrace skill with release builds and sound cues

Use release builds for accurate profiling, add ProGuard keep rules
for btrace and Sentry class names, increase trace duration to 30s,
and play a Ping sound synced to the actual trace start.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* chore: Update btrace-perfetto skill with debug builds and trace comparison

Prefer debug builds for richer tracing instrumentation (Handler,
MessageQueue, Lock slices). Add trace_processor prerequisite for local
querying. Add Step 6 with SQL queries and comparison table generation.
Include sampling rate reference and additional troubleshooting entries.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* fix(gestures): Suppress fling after multi-touch to prevent misclassified swipes

The ACTION_POINTER_DOWN handler suppressed taps but not flings. When
the last finger lifts quickly after a pinch-to-zoom, the velocity check
in ACTION_UP could fire onFling, causing SentryGestureListener to
misclassify the gesture as a swipe breadcrumb.

Add ignoreUpEvent flag mirroring GestureDetector's mIgnoreNextUpEvent
to skip the entire UP handler after multi-touch.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

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Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>