feat: LED strips — editor notes, docs, demo, smokes, golden scenes, profile (#780)

Stage 5 of #780.

- Import summary: «Strips left unbound after import: {n}» from the backend
  `unbound_led_strips` count; «Optimize plans» reports strips passing
  through walls per space and edits none (AC16).
- Linear field for long strips (ТЗ §13.2): pieces of at most the radius
  along the polyline, emitters thinned to r/4, each piece clipped to the
  visibility fans of its own emitters as separate clipPath children (no
  boolean pass per piece), one floor clip for the whole layer, no fan at
  all where nothing blocks within the radius; a grid index of body faces
  and boxed inside tests; unchanged fields skip re-diffing. 50×50 on the
  large house: first stable frame ~1.4 s, warm space ~1.1 s locally.
- led-strips-v1 profile: demo/benchmark_led_strips.mjs with the derived
  large-house fixture (10×5, 50×50, none), absolute limits of the ТЗ table
  in demo/performance/budgets-led-strips.json, exact counters (zero
  recomputes on HA ticks/camera/colour, ≤50 cache entries, no growth over
  20 cycles); added to the full performance workflow.
- Bundle: LAZY_LED_GZIP_CEILING 10 KiB, LAZY_LED_EDITOR_GZIP_CEILING 11 KiB
  (measured + 10 %, rounded up); overlaps with the initial and editor
  graphs refused; the lazy editor graph stays inside its ceiling.
- Smokes smoke_led_strip_draw/bind/glow, linked in smoke-links; 13 mutants
  in the registry (7 browser guards in the inventory); config field registry
  entry `spaces[].led_strips`.
- Golden: five new scenes on the `golden-led` space of the visual fixture
  (`ledStrips` option, the designer's four strips on #868D94), matrix v71.
- Docs: LIGHT, DEVICE-PRESENTATION, USER-GUIDE (en/ru), UX-MODES,
  ARCHITECTURE, ISOMETRIC, CONFIG-COMPATIBILITY, TOUCH-SUPPORT, demo/stand
  README, performance README; docs/design/led-strips with the unchanged
  designer archive, two paired frames and ACCEPTANCE.md; both changelogs.

Issue: #780
User-Visible: yes

.github/workflows/performance.yml

@@ -48,6 +48,7 @@ jobs:
           - overlay
           - space-default
           - space-glow
+          - led-strips
     steps:
       - name: Check out candidate
         uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7
@@ -175,6 +176,14 @@ jobs:
                 cp ../artifacts/performance/space-glow-candidate.json ../artifacts/performance/space-glow-baseline.json
               fi
               ;;
+            led-strips)
+              # #780 led-strips-v1: base predates LED strips, so the profile is
+              # judged by its absolute limits inside the runner; the zero-LED
+              # View stays covered by the relative interaction profile above.
+              npm run benchmark:led-strips -- --size=10x5 --samples=7 --warmups=1 --output=../artifacts/performance/led-strips-10x5.json
+              npm run benchmark:led-strips -- --size=50x50 --samples=7 --warmups=1 --output=../artifacts/performance/led-strips-50x50.json
+              npm run benchmark:led-strips -- --size=none --samples=7 --warmups=1 --output=../artifacts/performance/led-strips-none.json
+              ;;
             *)
               echo "::error::Unknown performance profile: $PROFILE"
               exit 1
@@ -217,6 +226,9 @@ jobs:
             space-glow)
               npm run benchmark:compare -- --budgets=demo/performance/budgets-large-space-card-glow.json --baseline=../artifacts/performance/space-glow-baseline.json --candidate=../artifacts/performance/space-glow-candidate.json --output=../artifacts/performance/space-glow-comparison.json
               ;;
+            led-strips)
+              echo "led-strips-v1: absolute limits and counters already enforced by the runner (budgets-led-strips.json)"
+              ;;
           esac
 
       - name: Upload full performance report