lacma-2026 page: kill all em dashes, collapse below-fold into dropdown

The landing page is now the Submittable form mirror first, reference
materials second. Above the fold: masthead, demo video, Application at
a Glance (every Submittable field with its answer inline). Everything
else (Pitch, Three Registers, live network metrics, AC Native feature
set, KidLisp cards, Lineage-of-ideas, Calendar, Budget, This-Lab's-
Lineage, Academic Spine, Submission-Form Version, Status) is now
wrapped in a single <details class="more"> dropdown labeled
"Extended reference."

Em dashes: every one of the 49 em dashes on the page is gone. Handled
in three passes:
1. Targeted prose fixes on the visible sections (masthead, demo tabs,
Application at a Glance, image captions). Parenthetical em dashes
became parens; clause-separator em dashes became periods, commas,
colons, or semicolons depending on context.
2. Bulk perl replacement of remaining " — " → " · " for below-fold
marker/separator usages (feat chips, CV-style rows, etc.).
3. Targeted fixes to the handful of below-fold prose spots where a
middle dot left awkward clause breaks (AC Native audio-waveform
list, Seymour Papert claim, condensed Submission-Form Version).

Metrics placeholder "—" (loading state before api/metrics resolves) →
"…" with matching update in the JS `fmt()` fallback.

Auto-open behavior: a small script listens for clicks on any in-page
anchor (and hashchange events). If the target lands inside the
<details>, the details opens automatically so "Full budget ↓" and
"Full calendar ↓" jumps from Glance land correctly.

Minor: "Public engagement" statement lost the "We propose" opener
(voice rule), "Three forms of public engagement." Added the
FOSS/MIT-on-GitHub claim as its closer.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>