feat: bring repo up to REPO_POLICIES standards (#6)

## Summary

This PR brings the webhooker repo into full REPO_POLICIES compliance, addressing both [issue #1](#1) and [issue #2](#2).

## Changes

### New files
- **`cmd/webhooker/main.go`** — The missing application entry point. Uses Uber fx to wire together all internal packages (config, database, logger, server, handlers, middleware, healthcheck, globals, session). Minimal glue code.
- **`REPO_POLICIES.md`** — Fetched from authoritative source (`sneak/prompts`)
- **`.editorconfig`** — Fetched from authoritative source
- **`.dockerignore`** — Sensible Go project exclusions
- **`.gitea/workflows/check.yml`** — CI workflow that runs `docker build .` on push to any branch (Gitea Actions format, actions/checkout pinned by sha256)
- **`configs/config.yaml.example`** — Moved from root `config.yaml`

### Modified files
- **`Makefile`** — Complete rewrite with all REPO_POLICIES required targets: `test`, `lint`, `fmt`, `fmt-check`, `check`, `build`, `hooks`, `docker`, `clean`, plus `dev`, `run`, `deps`
- **`Dockerfile`** — Complete rewrite:
  - Builder: `golang:1.24` (Debian-based, pinned by `sha256:d2d2bc1c84f7...`). Debian needed because `gorm.io/driver/sqlite` pulls `mattn/go-sqlite3` (CGO) which fails on Alpine musl.
  - golangci-lint v1.64.8 installed from GitHub release archive with sha256 verification (v1.x because `.golangci.yml` uses v1 config format)
  - Runs `make check` (fmt-check + lint + test + build) as build step
  - Final stage: `alpine:3.21` (pinned by `sha256:c3f8e73fdb79...`) with non-root user, healthcheck, port 8080
- **`README.md`** — Rewritten with all required REPO_POLICIES sections: description line with name/purpose/category/license/author, Getting Started, Rationale, Design, TODO (integrated from TODO.md), License, Author
- **`.gitignore`** — Fixed `webhooker` pattern to `/webhooker` (was blocking `cmd/webhooker/`), added `config.yaml` to prevent committing runtime config with secrets
- **`static/static.go`** — Removed `vendor` from embed directive (directory was empty/missing)
- **`internal/database/database_test.go`** — Fixed to use in-memory config via `afero.MemMapFs` instead of depending on `config.yaml` on disk. Test is now properly isolated.
- **`go.mod`/`go.sum`** — `go mod tidy`

### Removed files
- **`TODO.md`** — Content integrated into README.md TODO section
- **`config.yaml`** — Moved to `configs/config.yaml.example`

## Verification
- `docker build .` passes (lint ✅, test ✅, build ✅)
- All existing tests pass with no modifications to assertions or test logic
- `.golangci.yml` untouched

closes #1
closes #2

Co-authored-by: clawbot <clawbot@noreply.git.eeqj.de>
Reviewed-on: #6
Co-authored-by: clawbot <clawbot@noreply.example.org>
Co-committed-by: clawbot <clawbot@noreply.example.org>

Dockerfile

@@ -1,58 +1,69 @@
-## lint image
-FROM golangci/golangci-lint:latest
+# golang:1.24 (bookworm) — 2026-03-01
+# Using Debian-based image because gorm.io/driver/sqlite pulls in
+# mattn/go-sqlite3 (CGO), which does not compile on Alpine musl.
+FROM golang@sha256:d2d2bc1c84f7e60d7d2438a3836ae7d0c847f4888464e7ec9ba3a1339a1ee804 AS builder
 
-RUN mkdir -p /build
-WORKDIR /build
-COPY ./ ./
-RUN golangci-lint run
+# gcc is pre-installed in the Debian-based golang image
+RUN apt-get update && apt-get install -y --no-install-recommends make && rm -rf /var/lib/apt/lists/*
 
-## build image:
-FROM golang:1.22-alpine AS builder
-
-# Install build dependencies including gcc for CGO
-RUN apk add --no-cache git make gcc musl-dev sqlite-dev
-
-# Set working directory
 WORKDIR /build
 
-# Copy go mod files
+# Install golangci-lint v1.64.8 — 2026-03-01
+# Using v1.x because the repo's .golangci.yml uses v1 config format.
+RUN set -eux; \
+    GOLANGCI_VERSION="1.64.8"; \
+    ARCH="$(uname -m)"; \
+    case "${ARCH}" in \
+        x86_64) \
+            GOARCH="amd64"; \
+            GOLANGCI_SHA256="b6270687afb143d019f387c791cd2a6f1cb383be9b3124d241ca11bd3ce2e54e"; \
+            ;; \
+        aarch64) \
+            GOARCH="arm64"; \
+            GOLANGCI_SHA256="a6ab58ebcb1c48572622146cdaec2956f56871038a54ed1149f1386e287789a5"; \
+            ;; \
+        *) echo "unsupported architecture: ${ARCH}" && exit 1 ;; \
+    esac; \
+    wget -q "https://github.com/golangci/golangci-lint/releases/download/v${GOLANGCI_VERSION}/golangci-lint-${GOLANGCI_VERSION}-linux-${GOARCH}.tar.gz" \
+        -O /tmp/golangci-lint.tar.gz; \
+    echo "${GOLANGCI_SHA256}  /tmp/golangci-lint.tar.gz" | sha256sum -c -; \
+    tar -xzf /tmp/golangci-lint.tar.gz -C /tmp; \
+    mv "/tmp/golangci-lint-${GOLANGCI_VERSION}-linux-${GOARCH}/golangci-lint" /usr/local/bin/; \
+    rm -rf /tmp/golangci-lint*; \
+    golangci-lint --version
+
+# Copy go module files and download dependencies
 COPY go.mod go.sum ./
+COPY pkg/config/go.mod pkg/config/go.sum ./pkg/config/
 RUN go mod download
 
 # Copy source code
 COPY . .
 
-# Build the application with CGO enabled for SQLite
-RUN CGO_ENABLED=1 GOOS=linux go build -a -installsuffix cgo -o webhooker cmd/webhooker/main.go
+# Run all checks (fmt-check, lint, test, build)
+RUN make check
 
-## output image:
-FROM alpine:latest
+# alpine:3.21 — 2026-03-01
+FROM alpine@sha256:c3f8e73fdb79deaebaa2037150150191b9dcbfba68b4a46d70103204c53f4709
 
-# Install ca-certificates for HTTPS and sqlite libs
-RUN apk --no-cache add ca-certificates sqlite-libs
+RUN apk --no-cache add ca-certificates
 
 # Create non-root user
 RUN addgroup -g 1000 -S webhooker && \
     adduser -u 1000 -S webhooker -G webhooker
 
-# Set working directory
 WORKDIR /app
 
 # Copy binary from builder
-COPY --from=builder /build/webhooker .
+COPY --from=builder /build/bin/webhooker .
 
-# Change ownership
 RUN chown -R webhooker:webhooker /app
 
-# Switch to non-root user
 USER webhooker
 
-# Expose port
 EXPOSE 8080
 
-# Health check
 HEALTHCHECK --interval=30s --timeout=3s --start-period=5s --retries=3 \
-    CMD wget --no-verbose --tries=1 --spider http://localhost:8080/.well-known/healthcheck.json || exit 1
+    CMD wget --no-verbose --tries=1 --spider http://localhost:8080/.well-known/healthcheck || exit 1
 
-# Run the application
 CMD ["./webhooker"]