feat(understand): room frames, the nearest panel and possible packages — what the field test asked for

The takeoffs were run again on a real P&ID pair (kept outside the repository)
and compared with the hand-made workbooks. The user chose how three gaps
should close:

- Rooms drawn as frames. A room label that no wall face holds takes the
  smallest closed, straight-sided polyline around it, provided it holds no
  other room number and is at least ten label heights a side (label+frame,
  0.8). A P&ID draws its rooms this way, so P&ID lengths are now cut at the
  frames rather than sent to the nearest label. An unnumbered mention inside
  a frame ('hot room') does not deny it.
- The nearest panel, flagged. cable_takeoff(panel_rule="nearest") is the
  default: a load that no callout places takes the nearest panel on the
  layout, among names with a panel prefix (is_panel_name: CP, JB, DB,
  MCC ...) or names a callout gives. The row is flagged panel_inferred, and
  an inferred panel never makes a package. panel_rule="stated" keeps the old
  behaviour. The takeoff_roundtrip gate and the cable correctness check read
  stated panels only: a guess is no evidence.
- Possible packages and detail copies. pipe_takeoff reports detail_copies:
  compact groups of tags drawn twice (repeated), and compact groups of one
  equipment's own parts, such as M150B, M150C and M150D of M150 (family). A
  vendor package or an equipment detail shows up this way. Nothing is
  removed until exclude_regions names a region. The runs left out go to the
  control rows as excluded_region and to excluded_m. The workbook's method
  sheet names the regions.

Each change has a synthetic test that failed first. Suite: 4986 passed, 1
xfailed. The inventory and the document numbers match (README: 4987
collected).

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

CHANGELOG.md

@@ -401,6 +401,28 @@ member. Spec: `docs/superpowers/specs/2026-09-24-v1.6-understand-design.md`.
     naming the room it serves, or a note pointing into a room. An unnumbered
     label naming equipment is no room. Without room faces, when the drawing
     numbers its rooms, only numbered labels take pieces.
+  - The bare Russian "to" before a panel (`к CP1`, `к щиту CP-2`) is a
+    wiring callout.
+- **Track H, what the field test asked for** (each with a synthetic test):
+  - **Rooms drawn as frames.** A room label no wall face holds takes the
+    smallest closed, straight-sided polyline around it that holds no other
+    room number and is at least ten label heights a side (`label+frame`,
+    confidence 0.8). This is how a P&ID draws its rooms, so P&ID lengths are
+    cut at the room frames.
+  - **The nearest panel, flagged.** `cable_takeoff(panel_rule="nearest")`,
+    the default: a load that no callout places, whose tag is on the layout,
+    takes the nearest panel there. Only names with a panel prefix
+    (`is_panel_name`: CP, JB, DB, MCC ...) or names a callout gives are
+    candidates. The row is flagged `panel_inferred`, and an inferred panel
+    never makes a package. `panel_rule="stated"` leaves such a load open. The
+    benchmark and the correctness check read stated panels only.
+  - **Possible packages and detail copies.** `pipe_takeoff` reports
+    `detail_copies`: compact groups of tags drawn twice (`repeated`), and
+    compact groups of one equipment's own parts, such as M150B, M150C and
+    M150D of M150 (`family`). A pasteurizer drawn in detail, whose internal
+    pipes its vendor supplies, shows up this way. Nothing is removed until
+    `exclude_regions=["D2"]` names it. The excluded runs go to the control
+    rows as `excluded_region` and are totalled in `excluded_m`.
 
 ### Changed