chore: reset version to 1.0.0 for initial public release

This marks version 1.0.0 as the first public release of the plugin.
Previous versions (1.0.0-3.0.0) were private development iterations.

Changes:
- Reset manifest.json version to 1.0.0
- Reset package.json version to 1.0.0
- Clear versions.json to single entry (1.0.0 -> 0.15.0)
- Rewrite CHANGELOG.md for public release
  - Remove private development history
  - Document all features as part of 1.0.0
  - Add future roadmap section

Git history is preserved to demonstrate:
- Development quality and security practices
- Comprehensive test coverage efforts
- Thoughtful evolution of features

This plugin implements MCP (Model Context Protocol) to expose
Obsidian vault operations via HTTP for AI assistants and other clients.

versions.json

@@ -1,8 +1,3 @@
 {
-	"1.0.0": "0.15.0",
-	"1.1.0": "0.15.0",
-	"1.2.0": "0.15.0",
-	"2.0.0": "0.15.0",
-	"2.1.0": "0.15.0",
-	"3.0.0": "0.15.0"
+	"1.0.0": "0.15.0"
 }