docs(skills): upgrade example stops claiming a connector sync ever ran

The worked R1 in the upgrade skill's examples walks a protocol-16
`connectors[].fieldMappings[].transform` source. Since the connector sync
keys retired, the chain removes all of `fieldMappings` after the `transform`
key, and the tombstone the author meets is that key's. The example said the
connector had been landing raw values and its report template verified the
decision with a "connector sync run"; no engine ever ran a connector-attached
sync, so both now say what is true. The file shrinks by 37 bytes (1197 to
1188 tokens) at the same 119 lines.

Claude-Session: https://claude.ai/code/session_01Sfe5YjBLwB9J3y8fvm2xq1
Co-authored-by: Claude <noreply@anthropic.com>

Author: claude

skills/objectstack-upgrade/references/examples-upgrade.md

@@ -16,10 +16,10 @@ The shape in a protocol-16 project:
 }
 ```
 
-The chain deletes the key (`field-mapping-transform-removed`) and the schema
-tombstones it, so the parse error *is* the prescription: the union had five
-members and **no runtime ever executed any of them**. The customer wrote it
-because they wanted a transformation, and that need is real regardless.
+The chain deletes the key (`field-mapping-transform-removed`), then all of
+`fieldMappings` (`connector-sync-keys-removed`), whose tombstone *is* the
+prescription: **nothing ever ran any connector field mapping**. The customer
+wrote it because they wanted a transformation, and that need is real regardless.
 
 The prescription names one live target; the rest is the business decision:
 
@@ -29,10 +29,10 @@ The prescription names one live target; the rest is the business decision:
 | multi-source, multi-stage transformation | **nothing** — the L2 ETL layer retired at 17, unexecuted. Do it where it runs: warehouse ELT, a `flow`, a job. |
 | nothing — the value was already correct | delete the key and record that the transformation never ran. |
 
-That third row is frequently the truth: the member never executed, so the
-connector has been landing raw values for as long as it has been running.
-Whether the downstream data is wrong is a question only the owner can answer —
-exactly the kind of finding the report exists to surface.
+That third row is frequently the truth: no connector sync ever ran, so no value
+ever passed through this mapping. Where the data really comes from, and whether
+it is right, only the owner can answer — exactly the kind of finding the report
+exists to surface.
 
 ### 3.4 The report — the human half
 
@@ -64,7 +64,7 @@ _N sites, M conversions. Ported into sources from `os migrate meta --out`._
 - **Options:** import-mapping `transform` · ETL step · delete
 - **Decision:** delete — owner confirmed the values arrive pre-scaled.
   _Decided by: <who>, <date>._
-- **Verified:** `os validate` green; connector sync run against staging, 200 rows, values unchanged.
+- **Verified:** `os validate` green; nothing ever read the key, so no data changes.
 
 ## 3 · Open decisions