refactor(canvas): promote collapsed to first-class NodeData field + edge rewire

Three follow-ups to PR #158 review:

1. Promote collapsed to NodeData.collapsed
   The flag was previously stashed inside NodeData.custom_colors, which is
   a colors/style object — semantically wrong. Move it to a first-class
   boolean on NodeData. Persistence keeps the existing API shape: serialize
   writes it into the custom_colors blob (alongside width/height/z_order,
   matching how groupRect already stashes layout metadata), and deserialize
   hoists it back. Legacy saves from the original PR shape load correctly.

2. Re-route cross-zone edges to the collapsed ancestor
   Previously any edge touching a hidden node was dropped, so a Zigbee
   coordinator outside a collapsed mesh lost all visible links to it.
   rewireEdgesForCollapse now walks each endpoint up the parentId chain to
   its nearest visible ancestor, surfaces a single stub edge on the
   collapsed zone, de-dupes parallel rewires (a 20-device mesh becomes one
   stub, not twenty), and drops edges that would self-loop on a zone or
   reference an orphan.

3. Revert package-lock.json churn
   The 63-line diff from the original PR was npm-version drift (libc
   arrays stripped from optional deps), unrelated to the feature.

Tests:
- canvasStore.collapse: updated to assert on data.collapsed.
- collapseFilter: 8 cases for visibility + 7 for edge rewire, covering
  cross-boundary, nested collapse, sibling self-loop, mesh dedup, and
  orphan endpoints.
- canvasSerializer.collapse: round-trip + legacy-shape compat.

frontend/package-lock.json

@@ -2520,6 +2520,9 @@
         "arm"
       ],
       "dev": true,
+      "libc": [
+        "glibc"
+      ],
       "license": "MIT",
       "optional": true,
       "os": [
@@ -2534,6 +2537,9 @@
         "arm"
       ],
       "dev": true,
+      "libc": [
+        "musl"
+      ],
       "license": "MIT",
       "optional": true,
       "os": [
@@ -2548,6 +2554,9 @@
         "arm64"
       ],
       "dev": true,
+      "libc": [
+        "glibc"
+      ],
       "license": "MIT",
       "optional": true,
       "os": [
@@ -2562,6 +2571,9 @@
         "arm64"
       ],
       "dev": true,
+      "libc": [
+        "musl"
+      ],
       "license": "MIT",
       "optional": true,
       "os": [
@@ -2576,6 +2588,9 @@
         "loong64"
       ],
       "dev": true,
+      "libc": [
+        "glibc"
+      ],
       "license": "MIT",
       "optional": true,
       "os": [
@@ -2590,6 +2605,9 @@
         "loong64"
       ],
       "dev": true,
+      "libc": [
+        "musl"
+      ],
       "license": "MIT",
       "optional": true,
       "os": [
@@ -2604,6 +2622,9 @@
         "ppc64"
       ],
       "dev": true,
+      "libc": [
+        "glibc"
+      ],
       "license": "MIT",
       "optional": true,
       "os": [
@@ -2618,6 +2639,9 @@
         "ppc64"
       ],
       "dev": true,
+      "libc": [
+        "musl"
+      ],
       "license": "MIT",
       "optional": true,
       "os": [
@@ -2632,6 +2656,9 @@
         "riscv64"
       ],
       "dev": true,
+      "libc": [
+        "glibc"
+      ],
       "license": "MIT",
       "optional": true,
       "os": [
@@ -2646,6 +2673,9 @@
         "riscv64"
       ],
       "dev": true,
+      "libc": [
+        "musl"
+      ],
       "license": "MIT",
       "optional": true,
       "os": [
@@ -2660,6 +2690,9 @@
         "s390x"
       ],
       "dev": true,
+      "libc": [
+        "glibc"
+      ],
       "license": "MIT",
       "optional": true,
       "os": [
@@ -2674,6 +2707,9 @@
         "x64"
       ],
       "dev": true,
+      "libc": [
+        "glibc"
+      ],
       "license": "MIT",
       "optional": true,
       "os": [
@@ -2688,6 +2724,9 @@
         "x64"
       ],
       "dev": true,
+      "libc": [
+        "musl"
+      ],
       "license": "MIT",
       "optional": true,
       "os": [
@@ -2936,6 +2975,9 @@
         "arm64"
       ],
       "dev": true,
+      "libc": [
+        "glibc"
+      ],
       "license": "MIT",
       "optional": true,
       "os": [
@@ -2953,6 +2995,9 @@
         "arm64"
       ],
       "dev": true,
+      "libc": [
+        "musl"
+      ],
       "license": "MIT",
       "optional": true,
       "os": [
@@ -2970,6 +3015,9 @@
         "x64"
       ],
       "dev": true,
+      "libc": [
+        "glibc"
+      ],
       "license": "MIT",
       "optional": true,
       "os": [
@@ -2987,6 +3035,9 @@
         "x64"
       ],
       "dev": true,
+      "libc": [
+        "musl"
+      ],
       "license": "MIT",
       "optional": true,
       "os": [
@@ -6884,6 +6935,9 @@
         "arm64"
       ],
       "dev": true,
+      "libc": [
+        "glibc"
+      ],
       "license": "MPL-2.0",
       "optional": true,
       "os": [
@@ -6905,6 +6959,9 @@
         "arm64"
       ],
       "dev": true,
+      "libc": [
+        "musl"
+      ],
       "license": "MPL-2.0",
       "optional": true,
       "os": [
@@ -6926,6 +6983,9 @@
         "x64"
       ],
       "dev": true,
+      "libc": [
+        "glibc"
+      ],
       "license": "MPL-2.0",
       "optional": true,
       "os": [
@@ -6947,6 +7007,9 @@
         "x64"
       ],
       "dev": true,
+      "libc": [
+        "musl"
+      ],
       "license": "MPL-2.0",
       "optional": true,
       "os": [