Update environment configuration to development mode and add CLAUDE.md for project guidance

.env

@@ -1,4 +1,4 @@
-APP_ENV=prod
+APP_ENV=dev
 APP_DEBUG=0
 APP_SECRET=changeme_replace_with_random_32char_string
 

CLAUDE.md

@@ -0,0 +1,73 @@
+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## Development
+
+```bash
+# Install dependencies (generates composer.lock if missing — commit it)
+composer install
+
+# Run dev server
+APP_ENV=dev php -S localhost:8080 -t public
+
+# Test the graph endpoint
+curl "http://localhost:8080/graph.svg?theme=dark" -o graph.svg
+curl "http://localhost:8080/health"
+```
+
+## Docker
+
+```bash
+# Build and run
+docker compose up -d --build
+
+# Force cache clear (clears the 1h filesystem cache)
+docker compose exec graph rm -rf var/cache/*
+
+# View logs
+docker compose logs -f graph
+```
+
+There is no `composer.lock` in the repo. If you add or change dependencies, run `composer install` locally and commit the resulting lock file — without it, Docker builds resolve versions fresh each time and may produce inconsistent results.
+
+The Dockerfile runs `composer install --no-scripts` (skipping Symfony post-install scripts) then `composer dump-autoload --optimize --no-dev` in the final stage. If `bin/console` fails with a missing class error inside the container, the most likely cause is the absent lock file causing an incomplete dependency resolution.
+
+## Architecture
+
+Single-controller Symfony app with no database. The request flow:
+
+```
+GET /graph.svg?theme=dark|light
+  └─ GraphController
+       ├─ host check (ALLOWED_HOSTS env, optional)
+       ├─ cache lookup (filesystem, 1h TTL, key = "graph_{theme}")
+       │    └─ on miss:
+       │         ├─ GitHubProvider  → GitHub GraphQL API (contributionCalendar query)
+       │         ├─ GitLabProvider  → GitLab REST /users/:id/events (paginated, 100/page)
+       │         └─ GiteaProvider   → Gitea REST /api/v1/users/:user/heatmap
+       │              each returns array<string, int>  (Y-m-d => count)
+       │              failures are caught and logged; remaining providers still render
+       │         └─ merge by date (sum counts across providers)
+       │         └─ SvgRenderer::render()
+       └─ Response: image/svg+xml, Cache-Control: public max-age=3600
+```
+
+**Provider activation:** a provider only runs when its env vars are non-empty. GitHub and GitLab require `_USER` + `_TOKEN`; Gitea additionally requires `_URL`. GitLab resolves a numeric user ID from the username via a `/api/v4/users?username=` lookup before fetching events.
+
+**SvgRenderer:** builds a 53-column × 7-row grid aligned so the last column always ends on the Saturday of the current week. Five intensity levels (0 contributions → level 0, 1–3 → 1, 4–6 → 2, 7–9 → 3, 10+ → 4) mapped to GitHub's exact colour tokens. No external assets — the SVG is fully self-contained.
+
+**Cache:** filesystem adapter (`var/cache/`), mounted as a Docker volume to survive container restarts. Theme is part of the cache key so dark and light are cached independently.
+
+## Environment variables
+
+| Variable | Required | Notes |
+|---|---|---|
+| `APP_SECRET` | Yes | 32+ char random string |
+| `GITHUB_USER` / `GITHUB_TOKEN` | For GitHub | Token scope: `read:user` |
+| `GITLAB_USER` / `GITLAB_TOKEN` | For GitLab | Token scopes: `read_user`, `read_api` |
+| `GITLAB_URL` | No | Defaults to `https://gitlab.com` |
+| `GITEA_USER` / `GITEA_TOKEN` / `GITEA_URL` | For Gitea | Token scope: `read:user` |
+| `ALLOWED_HOSTS` | No | Comma-separated hostnames; empty = allow all |
+
+Copy `.env` to `.env.local` for local development — `.env.local` is gitignored.

README.md

@@ -6,7 +6,7 @@ A self-hosted Symfony service that merges contribution data from **GitHub**, **G
 https://your-host/graph.svg?theme=dark
 ```
 
-![Example graph](https://img.shields.io/badge/output-SVG%20heatmap-39d353?style=flat-square)
+![Example graph](https://gitgraph.arthurerlich/graph.svg)
 
 ---