feat(ui): add relationship management features in schema editor

- Implement functionality to create, update, delete, and view relationships between tables.
- Introduce new UI screens for managing relationships, including forms for adding and editing relationships.
- Enhance table editor with navigation to relationship management.
- Ensure relationships are displayed in a structured table format for better usability.

GODOC.md

@@ -0,0 +1,196 @@
+# RelSpec API Documentation (godoc)
+
+This document explains how to access and use the RelSpec API documentation.
+
+## Viewing Documentation Locally
+
+### Using `go doc` Command Line
+
+View package documentation:
+```bash
+# Main package overview
+go doc
+
+# Specific package
+go doc ./pkg/models
+go doc ./pkg/readers
+go doc ./pkg/writers
+go doc ./pkg/ui
+
+# Specific type or function
+go doc ./pkg/models Database
+go doc ./pkg/readers Reader
+go doc ./pkg/writers Writer
+```
+
+View all documentation for a package:
+```bash
+go doc -all ./pkg/models
+go doc -all ./pkg/readers
+go doc -all ./pkg/writers
+```
+
+### Using `godoc` Web Server
+
+**Quick Start (Recommended):**
+```bash
+make godoc
+```
+
+This will automatically install godoc if needed and start the server on port 6060.
+
+**Manual Installation:**
+```bash
+go install golang.org/x/tools/cmd/godoc@latest
+godoc -http=:6060
+```
+
+Then open your browser to:
+```
+http://localhost:6060/pkg/git.warky.dev/wdevs/relspecgo/
+```
+
+## Package Documentation
+
+### Core Packages
+
+- **`pkg/models`** - Core data structures (Database, Schema, Table, Column, etc.)
+- **`pkg/readers`** - Input format readers (dbml, pgsql, gorm, prisma, etc.)
+- **`pkg/writers`** - Output format writers (dbml, pgsql, gorm, prisma, etc.)
+
+### Utility Packages
+
+- **`pkg/diff`** - Schema comparison and difference detection
+- **`pkg/merge`** - Schema merging utilities
+- **`pkg/transform`** - Validation and normalization
+- **`pkg/ui`** - Interactive terminal UI for schema editing
+
+### Support Packages
+
+- **`pkg/pgsql`** - PostgreSQL-specific utilities
+- **`pkg/inspector`** - Database introspection capabilities
+- **`pkg/reflectutil`** - Reflection utilities for Go code analysis
+- **`pkg/commontypes`** - Shared type definitions
+
+### Reader Implementations
+
+Each reader is in its own subpackage under `pkg/readers/`:
+
+- `pkg/readers/dbml` - DBML format reader
+- `pkg/readers/dctx` - DCTX format reader
+- `pkg/readers/drawdb` - DrawDB JSON reader
+- `pkg/readers/graphql` - GraphQL schema reader
+- `pkg/readers/json` - JSON schema reader
+- `pkg/readers/yaml` - YAML schema reader
+- `pkg/readers/gorm` - Go GORM models reader
+- `pkg/readers/bun` - Go Bun models reader
+- `pkg/readers/drizzle` - TypeScript Drizzle ORM reader
+- `pkg/readers/prisma` - Prisma schema reader
+- `pkg/readers/typeorm` - TypeScript TypeORM reader
+- `pkg/readers/pgsql` - PostgreSQL database reader
+- `pkg/readers/sqlite` - SQLite database reader
+
+### Writer Implementations
+
+Each writer is in its own subpackage under `pkg/writers/`:
+
+- `pkg/writers/dbml` - DBML format writer
+- `pkg/writers/dctx` - DCTX format writer
+- `pkg/writers/drawdb` - DrawDB JSON writer
+- `pkg/writers/graphql` - GraphQL schema writer
+- `pkg/writers/json` - JSON schema writer
+- `pkg/writers/yaml` - YAML schema writer
+- `pkg/writers/gorm` - Go GORM models writer
+- `pkg/writers/bun` - Go Bun models writer
+- `pkg/writers/drizzle` - TypeScript Drizzle ORM writer
+- `pkg/writers/prisma` - Prisma schema writer
+- `pkg/writers/typeorm` - TypeScript TypeORM writer
+- `pkg/writers/pgsql` - PostgreSQL SQL writer
+- `pkg/writers/sqlite` - SQLite SQL writer
+
+## Usage Examples
+
+### Reading a Schema
+
+```go
+import (
+    "git.warky.dev/wdevs/relspecgo/pkg/readers"
+    "git.warky.dev/wdevs/relspecgo/pkg/readers/dbml"
+)
+
+reader := dbml.NewReader(&readers.ReaderOptions{
+    FilePath: "schema.dbml",
+})
+db, err := reader.ReadDatabase()
+```
+
+### Writing a Schema
+
+```go
+import (
+    "git.warky.dev/wdevs/relspecgo/pkg/writers"
+    "git.warky.dev/wdevs/relspecgo/pkg/writers/gorm"
+)
+
+writer := gorm.NewWriter(&writers.WriterOptions{
+    OutputPath:  "./models",
+    PackageName: "models",
+})
+err := writer.WriteDatabase(db)
+```
+
+### Comparing Schemas
+
+```go
+import "git.warky.dev/wdevs/relspecgo/pkg/diff"
+
+result := diff.CompareDatabases(sourceDB, targetDB)
+err := diff.FormatDiff(result, diff.OutputFormatText, os.Stdout)
+```
+
+### Merging Schemas
+
+```go
+import "git.warky.dev/wdevs/relspecgo/pkg/merge"
+
+result := merge.MergeDatabases(targetDB, sourceDB, nil)
+fmt.Printf("Added %d tables\n", result.TablesAdded)
+```
+
+## Documentation Standards
+
+All public APIs follow Go documentation conventions:
+
+- Package documentation in `doc.go` files
+- Type, function, and method comments start with the item name
+- Examples where applicable
+- Clear description of parameters and return values
+- Usage notes and caveats where relevant
+
+## Generating Documentation
+
+To regenerate documentation after code changes:
+
+```bash
+# Verify documentation builds correctly
+go doc -all ./pkg/... > /dev/null
+
+# Check for undocumented exports
+go vet ./...
+```
+
+## Contributing Documentation
+
+When adding new packages or exported items:
+
+1. Add package documentation in a `doc.go` file
+2. Document all exported types, functions, and methods
+3. Include usage examples for complex APIs
+4. Follow Go documentation style guide
+5. Verify with `go doc` before committing
+
+## References
+
+- [Go Documentation Guide](https://go.dev/doc/comment)
+- [Effective Go - Commentary](https://go.dev/doc/effective_go#commentary)
+- [godoc Documentation](https://pkg.go.dev/golang.org/x/tools/cmd/godoc)