feat(understand): cable_takeoff - one row per load, rounded to the metre

cable_rows reads each load's power, phases, voltage, neutral and VFD from the
P&ID's electrical texts near its tag, and its panel from the layout's wiring
callouts (else the P&ID's), names normalised CP 1 -> CP-1. The length is the
Manhattan distance on the layout from the tag to its panel, and the cable
ROUNDUP(length x (1 + allowance)) to the metre, on the length rounded to
1e-6 m so binary noise never buys a metre. Power is never invented: a load
with no stated kW keeps an empty cell and an open item. Without a layout the
lengths stay empty with an open item per row. Room and panel totals count a
panel package's power once, never its children's as well; the rule is on the
method sheet. Sections only from the caller's section_rules - no standard
table exists here.

The workbook gains the cable shape (Metraj, Ozet by room and panel, Kontrol
as the open-items list, Metodoloji) in the same three languages;
cable_takeoff joins SECTION 27. Inventory regenerated; README snapshot 243
tools (238 advertised); registry snapshot analysis: 14.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FKFStjEFzpGyLq5bMpWxTd

docs/tool-inventory.json

@@ -3,13 +3,13 @@
   "schema_version": 1,
   "package_version": "1.5.1",
   "totals": {
-    "tools": 242,
+    "tools": 243,
     "resources": 8,
     "prompts": 5,
     "groups": 26
   },
   "groups": {
-    "analysis": 13,
+    "analysis": 14,
     "architecture": 12,
     "batch": 3,
     "blocks": 9,
@@ -543,6 +543,21 @@
         "destructiveHint": false
       }
     },
+    {
+      "name": "cable_takeoff",
+      "group": "analysis",
+      "cost": "safe",
+      "summary": "Cable takeoff: one row per load, Manhattan length to its panel, rounded up to the metre.",
+      "tags": [
+        "analysis",
+        "plant"
+      ],
+      "annotations": {
+        "title": "Plant: Cable Takeoff",
+        "readOnlyHint": false,
+        "destructiveHint": false
+      }
+    },
     {
       "name": "cad_batch",
       "group": "batch",