Add semantic configuration profile comparison

docs/config.md

@@ -48,6 +48,9 @@ the durable copied session input.
 sources` use the same `--config`, `--campaign`, `--campaign-file`, and
 `--profile` selection rules as pipeline commands, but do not select, discover,
 or load a session. They do not read credential values or create runtime state.
+`narratio config diff <left-profile> <right-profile>` uses the same pipeline and
+campaign selectors, resolves each named profile independently from one parsed
+root source set, and does not accept a separate `--profile` flag.
 
 Campaign selection is optional only when the resolved pipeline has no
 `scriptorium.artifact_families`. When families are declared, Narratio selects a
@@ -60,9 +63,17 @@ composition and family declarations omitted. `config sources` prints a stable
 source projection instead of effective values: root/import/profile/default
 ownership plus campaign/party and generated-family records. Canonical derived
 players trace to the party; a legacy configured players file is explicitly
-marked as a legacy player source. The [CLI reference](cli.md#config-validate-config-show-and-config-sources)
+marked as a legacy player source. The [CLI reference](cli.md#config-validate-config-show-config-sources-and-config-diff)
 owns command syntax and output conventions.
 
+`config diff` compares normalized field values rather than YAML text or source
+ownership. It emits sorted `added`, `removed`, and `changed` records, uses
+compact deterministic JSON values, treats lists atomically, and reports `no
+differences` when the complete effective configurations are equal. Concrete
+family members and generated publish rules participate after expansion; moving
+an equal value between eligible root/import sources does not create a
+difference.
+
 ### Identity segments
 
 Campaign IDs (`campaign_id` and `default_campaign_id`), session IDs, previous