Initialize project skeleton with CLI and documentation

Add initial project structure including:
- Go module with Cobra CLI dependency
- Root command and main entrypoint
- Basic documentation (README, AGENTS.md, architecture, decisions,
  development, roadmap)
- Configuration example and gitignore
- Tool version management with mise
- Comprehensive project rules and conventions

docs/development.md

@@ -0,0 +1,37 @@
+# Development
+
+## Prerequisites
+
+- Go 1.26.2 (pinned in `mise.toml`)
+- `mise` (https://mise.jdx.dev) — run `mise install` to install toolchain
+
+## Build
+
+```bash
+go build ./...
+go build -o mygo .
+```
+
+## Test
+
+```bash
+go test ./...
+go test -v -run TestName ./internal/...
+```
+
+## Lint & Format
+
+```bash
+go vet ./...
+go fmt ./...
+```
+
+## Config
+
+Server config is in `config.yaml` (symlink to `config.example.yaml` in development environment).
+
+```
+server:
+    host: 0.0.0.0
+    port: 10086
+```