CapCut-parity effects, transitions, animations, and text-reveal engine

[maubrickastuto]

Summary

• Adds the packaged two-input transition shader runtime, 15 new transitions, 18 new effects, 18 new filters, and 24 new animation presets, closing most of the gap with CapCut's own library.
• Unlocks the Effects tab on text clips and adds a per-word text-reveal engine: a baked reveal-order texture (mirroring the existing colour LUT pipeline) read by a new reveal_order() WGSL helper, plus the concat.word-reveal package (Fade / Blur / Typewriter styles).
• Adds frame.clip_time to the shader frame uniform - seconds since the layer's own clip began, alongside the existing absolute frame.time - so a one-shot look can size itself to however long its clip has been on screen. concat.word-reveal uses this: it now starts the instant the clip does and finishes over a duration in seconds, with no manual scrub or keyframing needed.
• Fixes a real encoder bug found while verifying the above: Encoder never set a packet's duration, so the muxer inferred the stream's total duration from the PTS span alone and came up one frame short at rates like 25fps and 29.97fps. Packet duration is now set explicitly before rescale_ts.
• Merges in 84 commits from origin/main that landed in parallel (a "one FramePlan describes the frame" compositor rewrite, HW decode, advanced export settings, and more), reconciled by hand where both sides touched the same code - not resolved by taking one side wholesale.

What a reviewer should know

• The transition runtime, reveal-map engine, and clip-relative time are all genuinely new engine plumbing, not just new content folders - worth a closer look at concat-core/src/shader.rs, concat-effects/src/shader.rs, and concat-render/src/gpu.rs.
• Per-effect-param keyframing (AppliedFilter.keys) was investigated but not built: the resolve layer already interpolates it, but the Effects/Filters panel has no keyable UI at all to write one. Flagged as a follow-up, not attempted here.
• Verified: the full test suite across every touched crate (400+ tests, including new GPU-only goldens for the reveal map, clip-relative time, and the full transition/effect catalogues), the concat-host export integration suite (real ffmpeg encode/decode round trips), cargo clippy -D warnings on every crate, and a full concat app build.

Test plan

• cargo test across concat-text, concat-core, concat-effects, concat-export, concat-project, concat-render, concat-media, concat-host
• cargo test -p concat-render --features gpu (GPU-only goldens, including the new reveal-map and clip-relative-time tests)
• cargo test -p concat-host --test export (real ffmpeg encode/decode round trips, including the encoder duration fix)
• cargo clippy -D warnings on every touched crate and the full concat app
• cargo check -p concat (full app build)

🤖 Generated with Claude Code