fix: the initial wall-model migration resolves every opening conflict itself (#316)

Implements spec revision 4 (green r4). §3.1 — a legacy open_spans/open_to cut
never zeroes the atom that carries an existing contour opening: the opening's
edges become atom boundaries, the door keeps its real wall and the zero run
continues on both sides. §3.2 — an ambiguous carrier resolves
deterministically: current host, then distance, thicker cm, smaller id.
§3.3 — an opening with no usable carrier persists unhosted: a valid degraded
v9 state, inert in the physics, rendered by its own x/y, kept by later writes
and re-placeable in the editor (backend schema accepts it). §3.4 — the
initial migration never throws over an opening; a post-v9 write that LOST its
carrier keeps the fail-closed opening-host refusal. The Python migration
mirror implements the same rules with byte-identical output (verified on the
span+door fixture including the segment id).

The new smoke replays #316 end to end: a conflicted space no longer blocks
drawing on an empty plan. The golden scene span-over-door-migrated-dark
renders the migrated fixture pinned byte-for-byte to the real writer; two
gate mutants revert §3.1 and §3.4 and are red by execution.

Issue: #316
User-Visible: yes

docs/CHANGELOG.md

@@ -7,6 +7,12 @@
   example one that still carried an orphan legacy border) instead of demanding
   a card update that was already installed
   ([#319](https://github.com/Matysh/houseplan-card/issues/319)).
+- Drawing works again everywhere: converting a plan to the new wall model no
+  longer stops on a legacy border/opening conflict. A door standing inside a
+  former «border» keeps its real wall (the gap continues on both sides), an
+  ambiguous carrier is resolved deterministically, and an opening with no
+  usable wall at all is kept as data — inert until you re-place it
+  ([#316](https://github.com/Matysh/houseplan-card/issues/316)).
 
 ## v1.68.0-beta.3 — 2026-08-26
 

docs/CHANGELOG.ru.md

@@ -13,6 +13,12 @@
   документа (например, с осиротевшей легаси-границей) вместо требования
   обновить уже обновлённую карточку
   ([#319](https://github.com/Matysh/houseplan-card/issues/319)).
+- Рисование снова работает везде: преобразование плана к новой модели стен
+  больше не останавливается на конфликте легаси-границы с проёмом. Дверь
+  внутри бывшей «границы» сохраняет настоящую стену (разрыв продолжается по
+  обе стороны), неоднозначный носитель выбирается детерминированно, а проём
+  вовсе без пригодной стены сохраняется в данных — бездействует, пока его не
+  переставят ([#316](https://github.com/Matysh/houseplan-card/issues/316)).
 
 ## v1.68.0-beta.3 — 2026-08-26
 

docs/CONFIG-COMPATIBILITY.md

@@ -90,9 +90,16 @@ transmit Glow and sunlight, while solid zero walls are exact line barriers.
 documents only. Explicit valid spans win; `open_to` expands to the full proven
 shared boundary only when spans are absent. The first structural write,
 confirmed **Optimize plans**, or import into a current target atomizes that
-geometry into stable `wall_segments[].cm=0`, preserves surviving IDs, verifies
-that no opening would acquire a zero host, and then removes both legacy fields
-in one transaction. A conflict rejects the complete candidate. Presentation,
+geometry into stable `wall_segments[].cm=0`, preserves surviving IDs, and then
+removes both legacy fields in one transaction. An opening never blocks that
+migration (#316): the atom carrying an existing opening keeps its positive
+thickness (the zero run continues on both sides), an ambiguous carrier is
+resolved deterministically (current host, then distance, thicker cm, smaller
+id), and an opening with no usable carrier at all persists **unhosted** — a
+valid degraded v9 state that is inert in the physics (no body, tunnel or cut),
+renders by its own `x/y`, survives later writes untouched and may be re-placed
+in the editor. Post-migration structural writes keep the fail-closed refusal
+for an opening that LOST its carrier. Presentation,
 marker and ordinary space-settings writes do not trigger the migration.
 
 There is deliberately no provenance flag. Existing v8 `cm:0` and atoms derived

docs/images/screenshots.json

@@ -2,7 +2,7 @@
   "version": 1,
   "fixture": "synthetic-only",
   "chromium": "151.0.7922.34",
-  "sourceFingerprint": "4e7b4a7dc71cb9f1bb89caddbac0e70fee49088369165368845fcf1988867577",
+  "sourceFingerprint": "1f20c9d64ca59363be3909accd069595b4fe18404ee7a28a5db479dac605661a",
   "captureScriptSha256": "ce2e9542fed9dade3085be87d16f69adb2ac8262893ad78ad966b1b9673f2983",
   "command": "npm run build && node demo/docs/capture.mjs",
   "scenarios": {
@@ -14,7 +14,7 @@
       },
       "theme": "dark",
       "language": "en",
-      "sourceSha256": "4e7b4a7dc71cb9f1bb89caddbac0e70fee49088369165368845fcf1988867577",
+      "sourceSha256": "1f20c9d64ca59363be3909accd069595b4fe18404ee7a28a5db479dac605661a",
       "imageSha256": "9190bd86a07b0cb0502019d76d3286c0542181e1b4a4f862077d9cefa120613c"
     },
     "view-touch": {
@@ -25,7 +25,7 @@
       },
       "theme": "dark",
       "language": "en",
-      "sourceSha256": "4e7b4a7dc71cb9f1bb89caddbac0e70fee49088369165368845fcf1988867577",
+      "sourceSha256": "1f20c9d64ca59363be3909accd069595b4fe18404ee7a28a5db479dac605661a",
       "imageSha256": "cfa2f77eb68df69ae9fc9b51ffe2f14df01f7b74444fd2b038cadc1e9dfee22b"
     },
     "space-create": {
@@ -36,7 +36,7 @@
       },
       "theme": "dark",
       "language": "en",
-      "sourceSha256": "4e7b4a7dc71cb9f1bb89caddbac0e70fee49088369165368845fcf1988867577",
+      "sourceSha256": "1f20c9d64ca59363be3909accd069595b4fe18404ee7a28a5db479dac605661a",
       "imageSha256": "a86d4211af24923d5048e9094d0d35f9b28129394d00cd72582a8f8c2dd7ff75"
     },
     "room-contour-close": {
@@ -47,7 +47,7 @@
       },
       "theme": "dark",
       "language": "en",
-      "sourceSha256": "4e7b4a7dc71cb9f1bb89caddbac0e70fee49088369165368845fcf1988867577",
+      "sourceSha256": "1f20c9d64ca59363be3909accd069595b4fe18404ee7a28a5db479dac605661a",
       "imageSha256": "c7effd4ccd19bcaff9138458583368aaab488dcb6fc7ea5ab766383cb5377ac4"
     },
     "plan-context-tray": {
@@ -58,7 +58,7 @@
       },
       "theme": "dark",
       "language": "en",
-      "sourceSha256": "4e7b4a7dc71cb9f1bb89caddbac0e70fee49088369165368845fcf1988867577",
+      "sourceSha256": "1f20c9d64ca59363be3909accd069595b4fe18404ee7a28a5db479dac605661a",
       "imageSha256": "af1194f073f00b03af02b949a072cffb21bfd29995aa65a067eaaaec74ef8490"
     },
     "device-editor": {
@@ -69,7 +69,7 @@
       },
       "theme": "dark",
       "language": "en",
-      "sourceSha256": "4e7b4a7dc71cb9f1bb89caddbac0e70fee49088369165368845fcf1988867577",
+      "sourceSha256": "1f20c9d64ca59363be3909accd069595b4fe18404ee7a28a5db479dac605661a",
       "imageSha256": "36ed21b66920ff2de9e3346cf6f27c67e64a9f81692599b9c70d8373f5eb7241"
     },
     "device-display-preview": {
@@ -80,7 +80,7 @@
       },
       "theme": "dark",
       "language": "en",
-      "sourceSha256": "4e7b4a7dc71cb9f1bb89caddbac0e70fee49088369165368845fcf1988867577",
+      "sourceSha256": "1f20c9d64ca59363be3909accd069595b4fe18404ee7a28a5db479dac605661a",
       "imageSha256": "7151c96dc048381f7a7070ecb85a82a890b2f4c703628f14fa472eb8dacbf3dc"
     },
     "background-editor": {
@@ -91,7 +91,7 @@
       },
       "theme": "dark",
       "language": "en",
-      "sourceSha256": "4e7b4a7dc71cb9f1bb89caddbac0e70fee49088369165368845fcf1988867577",
+      "sourceSha256": "1f20c9d64ca59363be3909accd069595b4fe18404ee7a28a5db479dac605661a",
       "imageSha256": "9f08f3f3711b100d68fb1a05af269e43e47d8f8d12c0cbe4f9ab557138722989"
     },
     "room-card": {
@@ -102,7 +102,7 @@
       },
       "theme": "dark",
       "language": "en",
-      "sourceSha256": "4e7b4a7dc71cb9f1bb89caddbac0e70fee49088369165368845fcf1988867577",
+      "sourceSha256": "1f20c9d64ca59363be3909accd069595b4fe18404ee7a28a5db479dac605661a",
       "imageSha256": "66d8b0a509909822ff6b891a483bad9d2c72b20f08e287355883aa5205c6cee0"
     },
     "device-info": {
@@ -113,7 +113,7 @@
       },
       "theme": "dark",
       "language": "en",
-      "sourceSha256": "4e7b4a7dc71cb9f1bb89caddbac0e70fee49088369165368845fcf1988867577",
+      "sourceSha256": "1f20c9d64ca59363be3909accd069595b4fe18404ee7a28a5db479dac605661a",
       "imageSha256": "83620033bb66edf7c804619261e4a62327049c178267f0837bd997627ffdc003"
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   }