Rear Dashcam 0.15.2 for Gen5W

Rear dashcam 0.15.2 for Gen5W head units (Android 4.4), as a NEMESIS package: the recorder service and the Dashcam playback app in one install.

Changes in this version:

Fix the camera covering Android Auto while recording

The dashcam now keeps recording without drawing the rear camera over Android Auto's projected video. A boot-started native helper makes only the camera display layer transparent, leaving the camera DMA ring and hardware encoder running. Camera alpha is restored before reverse/camera-button handoff and when the recorder disconnects or dies. Video routing, overlay priority and SurfaceFlinger stay at their normal settings.

Reboot the head unit after installing or updating. The display helper needs the CAP_SYS_RAWIO capability NEMESIS grants services started at boot. Normal recording continues if alpha control is unavailable; Camera Debug reports now include the helper's diagnostics.

Other changes:

• Faster reverse detection: 50 ms polling while the recorder owns the camera, with slower polling for other work and idle operation.
• Lower overhead: batched native frame-detection hashes, bulk DMA strip reads, and no hidden debug-preview frame copies behind projection.
• Record to /dev/null test mode in Camera Debug for wired Android Auto without a flash drive. Camera and hardware encoding continue, but nothing is saved. USB insertion disables the test, even with the app closed.
• Clear no-drive status, green null-recording/red drive-recording indicators, stable fixed-width recording controls, and acknowledged on/off transitions without stale-poll flicker.
• Saved (0), dimmed playback controls without a drive, and updated Camera Debug, Save Report and Play Latest labels.
• Expanded TECHNICAL.md documenting boot privileges, device-tree validation, register addresses/masks, socket ownership, privilege drop and recovery behavior.

Validation: native conversion/hash/register-guard tests, null-mode cancellation/restart tests and recording-command transition tests passed. A live hardware-encoded test sustained 20 fps without dropped or torn frames; wired Android Auto, stock-camera handoff and recorder-death cleanup were checked on the NEEV23 head unit. CarPlay and other head units were not validated in this session.

Install over ADB with nemesis install --update dashcam-0.15.2.zip, or by USB: extract dashcam-0.15.2-usb.zip onto the root of a FAT32/exFAT drive and plug it in. Reboot the head unit after installing or updating to activate the camera overlay fix. Recordings and the recording on/off setting carry over when you update. Check downloads against SHA256SUMS. DashcamPlayer.apk is the app on its own; the package already contains it.

If the reverse camera ever fails to come up, stop and report it, and uninstall the package until it's fixed. Details in the README.