fix(cf-edit): reject add-childObject when object file is missing

cf-edit add-childObject was a low-level XML-manipulation operation
with no file-existence validation — callers could register a reference
to any Type.Name in Configuration.xml's ChildObjects without the
underlying file existing on disk. Platform then refused to load:
"Файл объекта не существует".

The 4 failing tests (add-objects, remove-object, add-default-role,
set-default-roles) all used this operation with fake references in
either main input or preRun, and had no way to pass verify-snapshots
because the cf-init-ed config had no actual object files.

User observation: this is the tests being wrong, not the skill.
meta-compile/role-compile/subsystem-compile already auto-register
every new object in Configuration.xml as part of their normal flow
(meta-compile.ps1:2949-3068, role-compile.ps1:667-747,
subsystem-compile.ps1:430-506). Nobody should be calling cf-edit
add-childObject to create a new object — they should be calling the
profile skill. cf-edit add-childObject is only for rare recovery
scenarios: rolled-back Configuration.xml with intact object files,
re-import from DB dump that clobbered the root but left srcfiles.

Changes:

1. cf-edit.ps1/py: Do-AddChildObject now checks that the target file
   exists at {ConfigDir}/{PluralDir}/{Name}.xml before registering.
   On miss, exits 1 with a message that names the expected path and
   points the user at the right skill (/meta-compile, /role-compile,
   or /subsystem-compile depending on type). TYPE_TO_DIR mapping for
   all 44 metadata types covers irregular plurals (FilterCriteria,
   BusinessProcesses, ChartsOfAccounts, ChartsOfCharacteristicTypes,
   ChartsOfCalculationTypes).

2. Tests: 4 existing cases rewritten to build realistic fixtures via
   meta-compile/role-compile preRun (both skills auto-register, so
   the resulting Configuration.xml already references the preRun
   objects). add-objects now exercises the round-trip recovery
   scenario: meta-compile creates Catalog.Товары and Document.ПриходТоваров
   (auto-registered) → cf-edit remove-childObject un-registers both
   (files remain) → main run re-registers via add-childObject. This
   tests exactly the rollback-recovery use case the operation exists for.

3. New add-missing-errors case: negative test with expectError:
   "Object file not found". Verifies the new hard-error path.

4. verify-snapshots.mjs: added symmetric expectError handling (runner.mjs
   already had it at line 514). If caseData.expectError is set,
   expect skill to fail; check stderr substring match; skip db-load
   and mark passed. Without this, negative tests would go red in
   verify-snapshots even though runner.mjs accepts them.

5. SKILL.md / reference.md: documented the new constraint and the
   redirection to profile skills. Kept mention of legitimate use case
   (rollback recovery).

Bumped cf-edit.ps1/py v1.0→v1.1.

Verification:
- runner --filter cf-edit (PS1): 2/6 → 7/7 (6 positive + 1 negative)
- runner --filter cf-edit --runtime python: 7/7 (dual-port clean)
- verify-snapshots --skill cf-edit: 2/6 → 7/7

With this landed P3 from debug/snapshot-verify/NEXT-STEPS.md is closed.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

tests/skills/cases/cf-edit/snapshots/add-default-role/Roles/ПолныеПрава.xml

@@ -0,0 +1,32 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<MetaDataObject xmlns="http://v8.1c.ru/8.3/MDClasses"
+        xmlns:app="http://v8.1c.ru/8.2/managed-application/core"
+        xmlns:cfg="http://v8.1c.ru/8.1/data/enterprise/current-config"
+        xmlns:cmi="http://v8.1c.ru/8.2/managed-application/cmi"
+        xmlns:ent="http://v8.1c.ru/8.1/data/enterprise"
+        xmlns:lf="http://v8.1c.ru/8.2/managed-application/logform"
+        xmlns:style="http://v8.1c.ru/8.1/data/ui/style"
+        xmlns:sys="http://v8.1c.ru/8.1/data/ui/fonts/system"
+        xmlns:v8="http://v8.1c.ru/8.1/data/core"
+        xmlns:v8ui="http://v8.1c.ru/8.1/data/ui"
+        xmlns:web="http://v8.1c.ru/8.1/data/ui/colors/web"
+        xmlns:win="http://v8.1c.ru/8.1/data/ui/colors/windows"
+        xmlns:xen="http://v8.1c.ru/8.3/xcf/enums"
+        xmlns:xpr="http://v8.1c.ru/8.3/xcf/predef"
+        xmlns:xr="http://v8.1c.ru/8.3/xcf/readable"
+        xmlns:xs="http://www.w3.org/2001/XMLSchema"
+        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+        version="2.17">
+    <Role uuid="UUID-001">
+        <Properties>
+            <Name>ПолныеПрава</Name>
+            <Synonym>
+                <v8:item>
+                    <v8:lang>ru</v8:lang>
+                    <v8:content>ПолныеПрава</v8:content>
+                </v8:item>
+            </Synonym>
+            <Comment/>
+        </Properties>
+    </Role>
+</MetaDataObject>

tests/skills/cases/cf-edit/snapshots/add-default-role/Roles/ПолныеПрава/Ext/Rights.xml

@@ -0,0 +1,9 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<Rights xmlns="http://v8.1c.ru/8.2/roles"
+        xmlns:xs="http://www.w3.org/2001/XMLSchema"
+        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+        xsi:type="Rights" version="2.17">
+    <setForNewObjects>false</setForNewObjects>
+    <setForAttributesByDefault>true</setForAttributesByDefault>
+    <independentRightsOfChildObjects>false</independentRightsOfChildObjects>
+</Rights>