Update: DCSS-driven cutscenes + hardening + docs

Significant follow-up work pushed to this branch:

What changed

• Replaced the FILM pre-scan entirely with a real DCSS parser. DCSS is the remaster's per-scene text script (lives in DarkEX.kpf at cutscene_scripts/<scene>.dcss) — I pulled the actual files out, matched the remaster's parser byte-for-byte (including the parse quirks like 00:00:58:827 and 00:1:50,487), and verified all 13 stock scripts parse identically. This also resolves @ifeldshteyn's comment about the missing getDuration() — that call went away with the rest of the scaling math.
• Dispatch against the video's intrinsic clock, not wall-clock, so music cues stay locked to the visible frame when the game hitches. Measured drift over full logo.ogv: 0–33 ms, bounded, no accumulation.
• Fixed musicvol: scale — was dividing by 127 (made every cutscene ~20% quiet), now divides by 100 to match the CUTSCENE.LST convention and the LFD path at cutscene_player.cpp:151.
• Parser hardening: sorted-on-load (defensive against hand-edited DCSS), # / // comment support, bounded string parsing, tolerant of locale typos.
• Locale-aware file lookup: logo_de.ogv, arcfly_de.srt etc. (matches remaster's convention).
• Merged master — picks up @luciusDXL's FileUtil::directoryExists rename from Fixing FileUtil exists check for windows. updating directoryExists ca… #590.

New documentation

Six markdown files under TheForceEngine/Documentation/markdown/remaster-cutscenes/:

• README.md — overview + quick starts
• architecture.md — pipeline diagram, path resolution, dispatch loop rationale, stock cutscene.lst reference
• dcss-format.md — complete format spec with stock annotated examples
• modding-guide.md — end-to-end walkthrough
• video-conversion.md — verified MP4 → OGV ffmpeg command lines (tested end-to-end with a 30s clip + hand-written DCSS, 3/3 cues fired with 0ms video drift)
• troubleshooting.md

Verification

• Debug + Release builds clean (Windows v143, SDK 10.0.26100.0).
• Full logo.ogv (1:53, 5 DCSS cues) played end-to-end under the DCSS_TIMING_TRACE instrumentation; see commit message for the drift table.
• Parser regression suite: 5 edge cases (stock files, unsorted, comments, truncated, empty buffer) — all pass.

Tracing flag DCSS_TIMING_TRACE in cutscene.cpp ships disabled; flip to 1 for per-cue drift logs when authoring new DCSS files.