refactor: remove 'obsidian' from plugin ID and update branding

- Change plugin ID from 'obsidian-mcp-server' to 'mcp-server'
- Remove 'Obsidian' from plugin description per guidelines
- Update documentation to use new plugin folder name
- Update installation paths to .obsidian/plugins/mcp-server/
- Update package name to match new plugin ID
- Simplify README title and description

package-lock.json

@@ -1,11 +1,11 @@
 {
-	"name": "obsidian-mcp-server",
+	"name": "mcp-server",
 	"version": "1.0.0",
 	"lockfileVersion": 3,
 	"requires": true,
 	"packages": {
 		"": {
-			"name": "obsidian-mcp-server",
+			"name": "mcp-server",
 			"version": "1.0.0",
 			"license": "MIT",
 			"dependencies": {