Convert Dolby Vision profile 7 to 8.1 on devices without a profile 7 decoder (#2017)

## Description

**On Amlogic boxes (S905X4 and similar) Dolby Vision Profile 7 does not
play as Dolby Vision.**
The server transcodes it, or, with "Direct play Dolby Vision Profile 7"
switched on by hand, the
decoder answers `NoSupport` and fallback ends in HDR10. Devices with a
native Profile 7 decoder,
such as the Shield, are not affected and nothing changes for them.

This PR converts Profile 7 to 8.1 on the fly. It has two halves and one
decision.

The preference `convertDolbyVisionProfile7` is proto field 6 in the
experimental settings, off by
default. In `WholphinRenderersFactory` the filter comes first in the
list, followed by the HDR10+
masking from #1876.

**What this PR does not do.** The enhancement layer is dropped; that is
the price of the
conversion, which is why devices with a native Profile 7 decoder are
left alone.
`BlockAdditional` (an enhancement layer outside the stream) is not read
— like the rest of
Wholphin today — so such a file stays HDR10, as it is now.

### Related issues

Closes #244

Builds on #1876 (the `BitstreamFilter` list). Related to #1540. @fanni42
asked for exactly this on
an S905X4 in #1876.

### Testing

**Hardware** — a debug build of this branch, Homatics box (Amlogic
S905X4, Android 14) + LG BX,
Jellyfin 12.1.0, a Profile 7 FEL remux with the enhancement layer in
band, played from the start
for 39 seconds. Only the new preference was switched on; manual "Direct
play Dolby Vision
Profile 7" was **off**:

* `DolbyVisionProfile7FilterTest` (14) — a fake rewriter on a direct
buffer: offset ≠ 0,
position/limit untouched, every "bytes stay as they were" branch,
three-byte start codes,
  `UnsatisfiedLinkError` tried once;
* `DolbyVisionProfile7ExtractorsFactoryTest` (5, mockk) — only the video
track is rewritten;
* `DolbyVisionProfile7ConversionTest` (6) — codec strings, DRM, `dvh1`.

CI in my fork ran on this branch plus a debug signing commit:
`pre-commit`,
`testDefaultDebugUnitTest` and `assembleDefaultDebug` are all green. The
hardware measurement
above is that build.

## Screenshots

The only UI change is one toggle in the experimental settings.

## AI or LLM usage

The code was written with Claude (Claude Code): the filter, the
extractor wrapper, the condition
and the tests. I reviewed every line and can explain it. It was tested
with the unit tests and
the hardware measurement above. This description was written by me in
Russian and translated
into English with the same assistant.

---------

Co-authored-by: Claude Fable 5.1 <noreply@anthropic.com>
Co-authored-by: Damontecres <damontecres@gmail.com>

app/src/main/res/values/strings.xml

@@ -503,6 +503,8 @@
     <string name="force_dovi_profile_7_summary">Ignores device compatibility checks</string>
     <string name="prefer_dovi_over_hdr10_plus">Prefer Dolby Vision over HDR10+</string>
     <string name="prefer_dovi_over_hdr10_plus_summary">Removes HDR10+ metadata from Dolby Vision videos, for TVs that otherwise play them as HDR10+</string>
+    <string name="convert_dovi_profile_7">Convert Dolby Vision Profile 7 to 8.1</string>
+    <string name="convert_dovi_profile_7_summary">Rewrites dual-layer Profile 7 into single-layer Profile 8.1 before the decoder and direct plays it, for devices whose decoder lists Profile 8 but not Profile 7</string>
 
     <string name="discover">Discover</string>
     <string name="request">Request</string>