Add semantic configuration profile comparison

docs/cli.md

@@ -20,7 +20,7 @@ Top-level commands:
 - `publish <session_id>`: force-run publish.
 - `clean <session_id>` or `clean --all`: remove local work/spool state.
 - `session <subcommand>`: session helper commands.
-- `config <subcommand>`: validate or display resolved pipeline configuration.
+- `config <subcommand>`: validate, display, source-trace, or compare resolved pipeline configuration.
 
 Session subcommands:
 
@@ -78,12 +78,13 @@ Commands with additional positionals keep their command-specific order:
 
 ## Command Reference
 
-### `config validate`, `config show`, and `config sources`
+### `config validate`, `config show`, `config sources`, and `config diff`
 
 ```bash
 narratio config validate [--config <pipeline.yml>] [--campaign <id> | --campaign-file <campaign.yml>] [--profile <name>]
 narratio config show [--config <pipeline.yml>] [--campaign <id> | --campaign-file <campaign.yml>] [--profile <name>]
 narratio config sources [--config <pipeline.yml>] [--campaign <id> | --campaign-file <campaign.yml>] [--profile <name>]
+narratio config diff <left-profile> <right-profile> [--config <pipeline.yml>] [--campaign <id> | --campaign-file <campaign.yml>]
 ```
 
 These commands resolve the selected profile, defaults, ordinary paths, and—if
@@ -112,6 +113,27 @@ legacy-player, and generated family ownership. A generated party member has
 one family record and one party record at the same logical path. The output
 never reads or prints secret values.
 
+`config diff` resolves both supplied profile names from one parsed root source
+set and compares their fully resolved, secret-free effective mappings. It does
+not accept `--profile`; the two positional names must be distinct, declared
+profiles. When party-driven families are present, both profiles must resolve to
+the same selected campaign and party. Use `--campaign-file` if profile-specific
+campaign configuration would otherwise select different files.
+
+Equal profiles print `no differences`. Otherwise, sorted tab-separated records
+use one of these forms, with compact JSON values:
+
+```text
+added    <path>    <right-value>
+removed  <path>    <left-value>
+changed  <path>    <left-value>    <right-value>
+```
+
+Mappings are flattened to their logical field paths; lists remain one atomic
+value. The command compares defaulted concrete artifacts and publish rules, not
+profile names, source-file layout, or formatting. It succeeds when differences
+are found, making it suitable for review and migration checks.
+
 ### `version`
 
 ```bash