feat: Implement foundation layer with domain entities and repository interfaces

- Add complete domain layer: Note, Vault, WikiLink, Tag, Frontmatter, Graph entities
- Implement repository interfaces for data access abstraction
- Create comprehensive configuration system with YAML and env support
- Add CLI entry point with signal handling and graceful shutdown
- Fix mermaid diagram syntax in design.md (array notation)
- Add CLAUDE.md for development guidance

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

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

go.mod

@@ -0,0 +1,32 @@
+module github.com/user/obsidian-mcp-server
+
+go 1.23.0
+
+require (
+	github.com/go-git/go-git/v5 v5.11.0
+	github.com/modelcontextprotocol/go-sdk v0.1.0
+	github.com/yuin/goldmark v1.6.0
+	go.abhg.dev/goldmark/frontmatter v0.1.0
+	gopkg.in/yaml.v3 v3.0.1
+)
+
+require (
+	github.com/ProtonMail/go-crypto v0.0.0-20230828082145-3c4c8a2d2371 // indirect
+	github.com/acomagu/bufpipe v1.0.4 // indirect
+	github.com/cloudflare/circl v1.3.3 // indirect
+	github.com/emirpasic/gods v1.18.1 // indirect
+	github.com/go-git/gcfg v1.5.1-0.20230307220236-3a3c6141e376 // indirect
+	github.com/go-git/go-billy/v5 v5.5.0 // indirect
+	github.com/golang/groupcache v0.0.0-20210331224755-41bb18bfe9da // indirect
+	github.com/jbenet/go-context v0.0.0-20150711004518-d14ea06fba99 // indirect
+	github.com/kevinburke/ssh_config v1.2.0 // indirect
+	github.com/pjbgf/sha1cd v0.3.0 // indirect
+	github.com/sergi/go-diff v1.1.0 // indirect
+	github.com/skeema/knownhosts v1.2.1 // indirect
+	github.com/xanzy/ssh-agent v0.3.3 // indirect
+	golang.org/x/crypto v0.16.0 // indirect
+	golang.org/x/net v0.19.0 // indirect
+	golang.org/x/sys v0.15.0 // indirect
+	golang.org/x/text v0.14.0 // indirect
+	gopkg.in/warnings.v0 v0.1.2 // indirect
+)