Release v0.0.8 - Adopt standard semver versioning

- Update release command to use standard semver with v prefix (v0.0.0 format)
- Add seamless migration from legacy non-prefixed versions (0.0.x -> v0.0.x)
- Document version format in release command instructions
- Bump version from 0.0.7 to v0.0.8 in package.json

Files modified:
- .claude/commands/release.md
- package.json

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

projects/firefox/public/manifest.json

@@ -2,7 +2,7 @@
   "manifest_version": 3,
   "name": "Plebeian Signer",
   "description": "Nostr Identity Manager & Signer",
-  "version": "0.0.7",
+  "version": "v0.0.8",
   "homepage_url": "https://git.mleku.dev/mleku/plebeian-signer",
   "options_page": "options.html",
   "permissions": [