feat: bring repo up to REPO_POLICIES standards

- Create cmd/webhooker/main.go with fx dependency injection wiring
- Add REPO_POLICIES.md, .editorconfig, .dockerignore
- Add .gitea/workflows/check.yml for CI (docker build on push)
- Rewrite Makefile with all required targets (test, lint, fmt, fmt-check,
  check, build, hooks, docker, clean, dev, run, deps)
- Rewrite Dockerfile with sha256-pinned base images, golangci-lint
  installed from verified release archive, make check as build step
- Fix README.md: add required sections (description, getting started,
  rationale, design, TODO, license, author)
- Integrate TODO.md content into README.md and remove TODO.md
- Move config.yaml to configs/config.yaml.example
- Fix .gitignore pattern for webhooker binary
- Fix static/static.go embed directive (remove empty vendor dir)
- Fix database test to use in-memory config (no filesystem dependency)

closes #1
closes #2

Makefile

@@ -1,39 +1,43 @@
-.PHONY: test fmt lint build run clean
+.PHONY: test lint fmt fmt-check check build run dev deps docker clean hooks
 
 # Default target
-test: lint
-	go test -v ./...
+.DEFAULT_GOAL := check
 
-fmt:
-	go fmt ./...
+test:
+	go test -v -race -timeout 30s ./...
 
 lint:
-	golangci-lint run
+	golangci-lint run --config .golangci.yml ./...
 
-build: test
-	go build -o bin/webhooker cmd/webhooker/main.go
+fmt:
+	gofmt -s -w .
+	@command -v goimports >/dev/null 2>&1 && goimports -w . || true
+
+fmt-check:
+	@test -z "$$(gofmt -s -l .)" || { echo "gofmt needed on:"; gofmt -s -l .; exit 1; }
+
+check: fmt-check lint test build
+
+build:
+	go build -o bin/webhooker ./cmd/webhooker
 
 run: build
 	./bin/webhooker
 
-clean:
-	rm -rf bin/
-
-# Development helpers
-.PHONY: dev deps
-
 dev:
-	go run cmd/webhooker/main.go
+	go run ./cmd/webhooker
 
 deps:
 	go mod download
 	go mod tidy
 
-# Docker targets
-.PHONY: docker-build docker-run
-
-docker-build:
+docker:
 	docker build -t webhooker:latest .
 
-docker-run: docker-build
-	docker run --rm -p 8080:8080 webhooker:latest 
+clean:
+	rm -rf bin/
+
+hooks:
+	@printf '#!/bin/sh\nmake check\n' > .git/hooks/pre-commit
+	@chmod +x .git/hooks/pre-commit
+	@echo "pre-commit hook installed"