Add dev:mobile command and bump minimum Obsidian version to 1.12.4

- Add `dev:mobile` (toggle mobile emulation) to dev command lists in
  SKILL.md (both copies) and README — present in command-reference.md
  but missing from the quick-reference tables
- Update minimum version recommendation from v1.12.0 to v1.12.4 in
  SKILL.md prerequisites table (1.12.4 is the latest stable as of
  2026-03-05; fixes Windows path detection, Unicode, startup bugs)
- Update README Obsidian badge from v1.12+ to v1.12.4+

https://claude.ai/code/session_01285FCGJmPvrLodTg4nVuc9

README.md

@@ -3,7 +3,7 @@
 A skill for AI coding agents that enables full control of [Obsidian](https://obsidian.md) vaults from the terminal using the official **Obsidian CLI** (v1.12+).
 
 ![Version](https://img.shields.io/badge/skill-v1.3.0-CC785C)
-![Obsidian](https://img.shields.io/badge/Obsidian-v1.12%2B-7C3AED?logo=obsidian&logoColor=white)
+![Obsidian](https://img.shields.io/badge/Obsidian-v1.12.4%2B-7C3AED?logo=obsidian&logoColor=white)
 ![Claude Code](https://img.shields.io/badge/Claude_Code-Plugin-D97757)
 ![Claude Code Plugin](https://img.shields.io/badge/Anthropic-Compatible-CC785C)
 
@@ -35,7 +35,7 @@ Covers **130+ commands** across all major areas:
 | **History** | `history`, `history:list`, `history:read`, `history:restore` |
 | **Workspace** | `workspace`, `tabs`, `tab:open` |
 | **Diff** | `diff` |
-| **Developer** | `eval`, `dev:screenshot`, `dev:debug`, `dev:console`, `dev:errors`, `dev:css`, `dev:dom`, `devtools` |
+| **Developer** | `eval`, `dev:screenshot`, `dev:debug`, `dev:console`, `dev:errors`, `dev:css`, `dev:dom`, `dev:mobile`, `devtools` |
 | **Vault** | `vault`, `vaults`, `version`, `reload`, `restart`, `recents`, `outline`, `wordcount` |
 
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