fix(playback): pick HEVC sample-entry tag from the client's DeviceProfile

[lostb1t]

Alternative to #411.

[Copilot]

🟡 Changes recommended

It introduces avoidable public-API expansion/breakage in device_profile (public trait method + public constants) that should be made backward-compatible and/or crate-private.

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Pull request overview

This PR adjusts HEVC stream-copy behavior in remux-server so the MP4 sample-entry fourcc (hvc1 vs hev1) is selected based on the requesting client’s DeviceProfile, then propagated through playback URLs/sessions into ffmpeg arguments and HLS CODECS signaling.

Changes:

• Add a per-session/per-transcode hevc_copy_tag propagated from DeviceProfile → querystring → TranscodeSession/params.
• Apply the resolved tag to ffmpeg -tag:v for HEVC stream-copy (HLS fMP4 path + progressive copy path).
• Update HLS master playlist CODECS generation to match the actual fourcc used for HEVC fMP4 segment sample entries; add unit tests for tag behavior.

File summaries

File	Description
crates/remux-server/src/playback/session.rs	Store the resolved HEVC copy tag on TranscodeSession.
crates/remux-server/src/playback/engine.rs	Thread tag into transcode params, apply -tag:v, and ensure master playlist CODECS matches; adds tests.
crates/remux-server/src/playback/decision.rs	Carry the resolved tag forward on the transcode URL as a query parameter.
crates/remux-server/src/device_profile.rs	Add DeviceProfileExt::hevc_copy_tag() and tag constants; implement logic using codec-profile conditions; adds tests.
crates/remux-server/src/api/playback.rs	Pass video_codec_tag query value into progressive transcode params.
crates/remux-server/src/api/hls.rs	Persist tag into TranscodeSession and into per-segment TranscodeParams.
crates/remux-sdks/src/remux/mod.rs	Extend query DTOs with video_codec_tag so the server can deserialize/forward it.

Review details

• Files reviewed: 7/7 changed files
• Comments generated: 2
• Review effort level: Lite

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[github-actions]

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docker pull ghcr.io/lostb1t/remux:pr-413

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