phase 0: project bootstrap

P0-01 Go module + cmd/server + cmd/agent skeletons + internal/ tree
P0-02 LICENSE (PolyForm NC 1.0.0), README, CONTRIBUTING
P0-03 golangci-lint, pre-commit, .editorconfig, .gitignore
P0-04 Gitea Actions CI: test (race+coverage), lint, cross-platform build matrix
P0-05 Dockerfile.server (multi-stage, distroless/static), docker-compose.yml
P0-06 Makefile with build/test/lint/fmt/run/release targets

build, vet, test, and cross-compile to linux/{amd64,arm64} + windows/amd64
all verified locally.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

.editorconfig

@@ -0,0 +1,18 @@
+root = true
+
+[*]
+charset = utf-8
+end_of_line = lf
+insert_final_newline = true
+trim_trailing_whitespace = true
+indent_style = space
+indent_size = 2
+
+[*.go]
+indent_style = tab
+
+[Makefile]
+indent_style = tab
+
+[*.{md,yml,yaml,json}]
+indent_size = 2