fix(ai skills): correct stale branch names, rg flags, and commit scope rules

Fixes deslop diffing against nonexistent main, an invalid rg --type tsx flag
in fix-merge-conflicts, a Codex-specific phrase leaking into the Claude/Cursor
inspect-elements description, and aligns commit-format with the required-scope
convention the commit skill and git history already use. Rewrites the readme
skill from 764 lines of Rails-specific guidance to a lean version matching
this Vite/Capacitor/Electron repo.

.codex/skills/deslop/SKILL.md

@@ -6,19 +6,19 @@ disable-model-invocation: true
 
 # Remove AI Code Slop
 
-Scan the diff against main and remove AI-generated slop introduced in this branch.
+Scan the diff against master and remove AI-generated slop introduced in this branch.
 
 ## Workflow
 
 1. **Get the diff**
 
    ```bash
-   git diff main...HEAD
+   git diff master...HEAD
    ```
 
    If there are also uncommitted changes, include them:
    ```bash
-   git diff main
+   git diff master
    ```
 
 2. **Scan each changed file** for the slop categories below