feat(image): sensor-level flip/mirror via MI_SNR_SetOrien (both backends)

[snokvist]

Summary

image.flip / image.mirror now work correctly on both backends. They
previously rode the VPE digital flip (MI_VPE_SetChannelParam mirror/flip),
which is unreliable on several sensor combos — on IMX335 (Star6E) flip
stalled the encoder outright (a brief flipped frame, then a hang).

Root cause of the stall was a per-frame MI_SNR_SetOrien "storm" (re-applying
orientation every frame for ~5s to fight a phantom "CUS3A clears orientation"
theory); on IMX335 that repeatedly rewrote the sensor's vertical-timing
register table mid-stream and wedged the encoder. It is not a flip-vs-VIF
hardware incompatibility.

Change

Program the sensor's own orientation register via MI_SNR_SetOrien, applied
once at bring-up on both backends:

• sensor_select: before MI_SNR_Enable, so the driver's init picks up the
  correct flip/mirror state.
• star6e_pipeline / maruko_pipeline: before the VPE channel starts.
• VPE digital flip stays disabled (param.mirror/flip = 0).

The sensor driver only rewrites orientation when we set it, so a single apply
holds for the life of the stream. A one-shot re-apply follows the discrete
MI_SNR_SetFps events that can reprogram sensor timing (Star6E live ISP-bin
reload; Maruko cold-boot fps kick).

No per-frame re-apply loop and no MI_SNR_GetOrien (it reads stale values
under AE I2C load on IMX335 — reports m=0/f=0 while the image is plainly held).
MI_VPE_SetChannelParam failure stays fatal.

Tests

• tests/test_sensor_select.c: test_orientation_applied_as_requested —
  unconditional apply for imx335/imx415, and no SetOrien call when neither
  is requested. 1645 tests pass.
• Build clean on star6e + maruko; make pre-pr gate OK (v0.16.0).

Device verification

• Star6E / IMX335 and Maruko / IMX415: flip + mirror both visually
  correct and stable — alive, stable PID, frames flowing, no orientation churn,
  no reboot.

🤖 Generated with Claude Code