REPO_POLICIES compliance audit (#40)

Brings the repository into compliance with REPO_POLICIES standards.

Closes [issue #39](#39).

## Changes

### Added files
- **REPO_POLICIES.md** — fetched from `sneak/prompts` (last_modified: 2026-02-22)
- **.editorconfig** — fetched from `sneak/prompts`, enforces 4-space indents (tabs for Makefile)
- **.dockerignore** — standard Go exclusions (.git/, bin/, *.md, LICENSE, .editorconfig, .gitignore)

### Makefile updates
- Added `fmt-check` target (read-only gofmt check)
- Added `hooks` target (installs pre-commit hook running `make check`)
- Added `docker` target (runs `docker build .`)
- Added `-timeout 30s` to both `test` and `check` targets
- Updated `.PHONY` list with all new targets

### Removed files
- **CLAUDE.md** — superseded by REPO_POLICIES.md
- **CONVENTIONS.md** — superseded by REPO_POLICIES.md

### README updates
- First line now includes project name, purpose, category (daemon), and author per REPO_POLICIES format
- Updated CONVENTIONS.md reference to REPO_POLICIES.md
- Added **License** section (pending author choice)
- Added **Author** section: [@sneak](https://sneak.berlin)

### Intentionally skipped
- **LICENSE file** — not created; license choice (MIT, GPL, or WTFPL) requires sneak's input

## Verification
- `docker build .` passes (all checks green: fmt, lint, tests, build)
- No changes to `.golangci.yml`, test assertions, or linter config

Co-authored-by: clawbot <clawbot@noreply.git.eeqj.de>
Co-authored-by: Jeffrey Paul <sneak@noreply.example.org>
Reviewed-on: #40
Co-authored-by: clawbot <clawbot@noreply.example.org>
Co-committed-by: clawbot <clawbot@noreply.example.org>

Makefile

@@ -1,4 +1,4 @@
-.PHONY: all build lint fmt test check clean
+.PHONY: all build lint fmt fmt-check test check clean hooks docker
 
 BINARY := dnswatcher
 VERSION := $(shell git describe --tags --always --dirty 2>/dev/null || echo "dev")
@@ -17,8 +17,11 @@ fmt:
 	gofmt -s -w .
 	goimports -w .
 
+fmt-check:
+	@test -z "$$(gofmt -l .)" || (echo "gofmt: files not formatted:" && gofmt -l . && exit 1)
+
 test:
-	go test -v -race -cover ./...
+	go test -v -race -timeout 30s -cover ./...
 
 # Check runs all validation without making changes
 # Used by CI and Docker build - fails if anything is wrong
@@ -28,10 +31,19 @@ check:
 	@echo "==> Running linter..."
 	golangci-lint run --config .golangci.yml ./...
 	@echo "==> Running tests..."
-	go test -v -race ./...
+	go test -v -race -timeout 30s ./...
 	@echo "==> Building..."
 	go build -ldflags "$(LDFLAGS)" -o /dev/null ./cmd/dnswatcher
 	@echo "==> All checks passed!"
 
 clean:
 	rm -rf bin/
+
+hooks:
+	@echo '#!/bin/sh' > .git/hooks/pre-commit
+	@echo 'make check' >> .git/hooks/pre-commit
+	@chmod +x .git/hooks/pre-commit
+	@echo "Pre-commit hook installed."
+
+docker:
+	docker build .