docs(fleet): add operator configuration guide (#789)

docs/fleet/how-to/customize-roles.md

@@ -2,8 +2,8 @@
 
 Mosaic resolves persona contracts through two layers:
 
-1. `fleet/roles/<canonical-class>.md` — seeded baseline contract.
-2. `fleet/roles.local/<canonical-class>.md` — operator override or custom role; this layer wins.
+1. fleet/roles/<canonical-class>.md — seeded baseline contract.
+2. fleet/roles.local/<canonical-class>.md — operator override or custom role; this layer wins.
 
 The same shared resolver is used by profile validation, provisioning, roster-v2 semantic validation,
 and launch-time persona injection.
@@ -34,11 +34,11 @@ A custom class remains supported when a readable contract exists for the exact i
 The release-notes role (`class: release-notes`) prepares operator-reviewed release copy.
 ```
 
-Save it as `fleet/roles.local/release-notes.md`, then reference `class: release-notes` and a matching
-`tool_policy: release-notes` in roster v2. Adding only a `LIBRARY.md` row is insufficient.
+Save it as `fleet/roles.local/release-notes.md`, then reference class: release-notes and a matching
+tool_policy: release-notes in roster v2. Adding only a `LIBRARY.md` row is insufficient.
 
 Names such as `worker`, `analyst`, and `canary` are not built-in aliases; they need genuine custom
-contracts. `agents[].alias`, Tess, and Ultron are display names and cannot select a class.
+contracts. agents[].alias, Tess, and Ultron are display names and cannot select a class.
 
 ## Validation and authority boundaries