re: a long voice cue is three presentations of one take, and our guard clips the first

Closes the last open question on the voice regions: why one cue s byte span
decodes to ~2.6x the movie s length.

The port measured, with controls including a cross-movie negative, that a
region s leading chunk is the TAIL of the full-length chunk that follows it --
r = 0.998 at a lag that puts it flush against that chunk s end, residual 16.7 dB
down over 84.5 s. They withdrew their own earlier 0.768, which came from a
search that scored best on the boundary of its own lag range.

Checked it here by an independent route that needs no decoder. If the leading
chunk is the tail of a full-length first stream, the whole leading stream should
be one complete take of chunk 1 s duration. For ADV: 504464 + 808304 = 1312768 B
at chunk 0 s byte rate of 9559.7 B/s is 137.323 s, against chunk 1 s measured
137.324 s. One millisecond over 137 seconds, from byte rates rather than from
envelope correlation.

And the byte structure settles the shape disc-wide. Counting stream starts inside
every inter-descriptor span: 258 hold exactly 1 stream, 28 hold exactly 3, and
nothing holds 2 or any other number. All 20 spans over 1.5 MB are 3-stream. The
95 movie regions decompose 70 + 8 + 17, and the 8 are independently the same 8
the first census found as bank-header-with-3-chunks.

So 359 s = 84.55 + 137.32 + 137.32: three presentations of one take, the first
clipped by resolve_movie_voice_region s own 1.5 MB guard.

Consequences recorded for the port: dropping the leading chunk is removing a
duplicate rather than truncating, so the hedge is lifted; but summing chunk 1
and chunk 2 is wrong, because they are the same take at different gain, not two
stems. Take one stream.

Also flags a coincidence I nearly built on: the 504464 B constant is structural,
not proportional -- ADV s proportional prediction lands within 8 bytes of it and
S00A s is 4305 B out.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01QsEPXWVaEpyfudtR6re1Pd

docs/re/data/voice-stream-cue-map.txt

@@ -48,3 +48,8 @@ cue span vs the 1.5 MB guard, and what the region actually starts at:
 
 cues over the 1.5 MB guard: 17, of which stream-opening: 17
 cues under the guard:      78, of which stream-opening: 0
+
+stream starts inside each cue's TRUE span (desc(N-1)..desc(N)):
+
+  all inter-descriptor spans:  {1: 258, 3: 28}
+  spans >= 1.5 MB (the long cues): {3: 20}