docs(skills): remove stale no-self-merge contract refs (GRO-2763)

Remove stale no-self-merge contract references left by org#17 (GRO-2377 fast-follow). Fixes coding-standards, sdlc, and devops skills.

skills/coding-standards/SKILL.md

@@ -4,7 +4,7 @@ description: >
   Engineering quality bar for GroomBook code: priority ordering of correctness
   vs. clarity vs. maintainability vs. performance vs. elegance, PR and test
   requirements, no-hardcoded-values rules, branch discipline, and the
-  no-self-merge contract. The uat→main merge-gate policy lives in the `sdlc`
+  PR self-merge rule. The uat→main merge-gate policy lives in the `sdlc`
   skill, not here.
 ---
 

skills/devops/SKILL.md

@@ -35,7 +35,7 @@ Use the `GITEA_TOKEN` environment variable for all Gitea operations — it is al
 tea pr create --base main --title "..." --body "... cc @cpfarhood"
 ```
 
-Gitea branch protection requires CI checks to pass. See `coding-standards` for the no-self-merge contract and the `cc @cpfarhood` rule.
+Gitea branch protection requires CI checks to pass. See `coding-standards` for the PR self-merge rule and the `cc @cpfarhood` rule.
 
 ## Infrastructure topology
 

skills/sdlc/SKILL.md

@@ -36,7 +36,7 @@ Three long-lived branches map to the three deployment environments:
 
 ## Pull requests
 
-All changes happen via pull request. Gitea branch protection requires CI checks to pass. See `coding-standards` for the no-self-merge contract and the `cc @cpfarhood` visibility rule.
+All changes happen via pull request. Gitea branch protection requires CI checks to pass. See `coding-standards` for the PR self-merge rule and the `cc @cpfarhood` visibility rule.
 
 ```bash
 tea pr create --base dev --title "..." --body "... cc @cpfarhood"