deploy/gitea: Gitea behind traefik, rproxy and servewaf, with its test (closes #178)

deploy/gitea/compose.yaml runs traefik, stock Gitea 1.27.3, rproxy and
servewaf on one network with a fixed subnet. Its containers skip
servewaf's checks; the network's gateway is left out of that range.
rproxy takes uploads of 2 GiB and 30 minutes, and cuts responses at 15
minutes. script/gitea-setup (make gitea-setup) brings the setup up and
checks it. docs/gitea.md is rewritten around the setup.

Judgement call: the Core Rule Set runs in detect mode, so it refuses nothing.
Judgement call: traefik serves its own certificate; no certificate resolver.
Partially verified: the image build failed three runs on Ubuntu's snapshot
service, so the checks ran only against a stand-in image with the same binary.

Model: opus-5-5

deploy/gitea/compose.yaml

@@ -0,0 +1,120 @@
+# Gitea behind traefik, with rproxy and servewaf in front of it.
+# docs/gitea.md says what each setting here does and why. Before starting it:
+#   - set SMALLWEBWAF_IMAGE to the smallwebwaf image, named by digest;
+#   - replace git.example.org with the site's host name;
+#   - replace each 10.99.0 with the first three numbers of a /24 subnet that
+#     no other network on the host uses.
+# Then run `docker compose up --detach` in this directory.
+# script/gitea-setup checks this setup.
+
+name: gitea
+
+x-logging: &logging
+    driver: json-file
+    options:
+        max-size: 10m
+        max-file: "5"
+
+services:
+    traefik:
+        # traefik v3.7.17, 2026-11-03
+        image: traefik@sha256:68ae5fe5b64ca166704b746a9e8afcd385e36b3f569a5691401bf652d57b3748
+        # traefik replaces the X-Forwarded-For header a visitor sends. Keep it
+        # so: otherwise a visitor could name an address on the shared network,
+        # and skip servewaf's checks.
+        command:
+            - --providers.docker.exposedbydefault=false
+            - --entrypoints.web.address=:80
+            - --entrypoints.web.http.redirections.entrypoint.to=websecure
+            - --entrypoints.websecure.address=:443
+            # Until a certificate resolver is added here, as for your other
+            # sites, traefik answers with a certificate it made itself.
+            - --entrypoints.websecure.http.tls=true
+            # traefik's own limit of 60 seconds for a whole request would cut
+            # off an upload long before rproxy's limit of 30 minutes.
+            - --entrypoints.websecure.transport.respondingTimeouts.readTimeout=30m
+        ports:
+            - 80:80
+            - 443:443
+        volumes:
+            - /var/run/docker.sock:/var/run/docker.sock:ro
+        networks:
+            shared:
+                # Containers on the shared network find traefik under the
+                # site's name, and so reach it from their own address.
+                aliases:
+                    - git.example.org
+        restart: unless-stopped
+
+    gitea:
+        # gitea 1.27.3, 2026-08-29
+        image: gitea/gitea@sha256:87a67ee09d3ae0d1df5fda5dcda3e2a1f9236a45b0a59025d6e00e46adc43bef
+        environment:
+            GITEA__server__ROOT_URL: https://git.example.org/
+            # Gitea starts at its defaults, with SQLite, instead of showing its
+            # install page to whoever opens it first.
+            GITEA__security__INSTALL_LOCK: "true"
+            # rproxy's address. Gitea then takes each visitor's address from
+            # the X-Real-Ip header traefik sets and rproxy passes on.
+            GITEA__security__REVERSE_PROXY_TRUSTED_PROXIES: 10.99.0.2
+        volumes:
+            - gitea-data:/data
+        networks:
+            - shared
+        restart: unless-stopped
+
+    rproxy:
+        image: ${SMALLWEBWAF_IMAGE:?set SMALLWEBWAF_IMAGE to the smallwebwaf image}
+        environment:
+            SWRP_WAF_BACKEND: http://servewaf:8080
+            SWRP_UPSTREAM_URL: http://gitea:3000
+            # Pushes, LFS objects, packages and release attachments of up to
+            # 2 GiB, sent in up to 30 minutes.
+            SWRP_MAX_REQUEST_SIZE: 2G
+            SWRP_MAX_REQUEST_TIME_MS: "1800000"
+            # 15 minutes for a clone or a download, half the default.
+            SWRP_MAX_RESPONSE_TIME_MS: "900000"
+        labels:
+            traefik.enable: "true"
+            traefik.http.routers.gitea.rule: Host(`git.example.org`)
+            traefik.http.routers.gitea.entrypoints: websecure
+            traefik.http.services.gitea.loadbalancer.server.port: "8080"
+        networks:
+            shared:
+                ipv4_address: 10.99.0.2
+        logging: *logging
+        restart: unless-stopped
+
+    servewaf:
+        image: ${SMALLWEBWAF_IMAGE:?set SMALLWEBWAF_IMAGE to the smallwebwaf image}
+        environment:
+            SMALLWEBWAF_COMMAND: servewaf
+            # The containers on the shared network skip the checks. Add the
+            # address of an automation fleet on another host here too; without
+            # that, the default request limits are sized for such a fleet.
+            SWWAF_ALLOW_NETS: 10.99.0.128/25
+            # In block mode the Core Rule Set refuses everyday Gitea searches
+            # and file names, and 31 refusals in a minute ban the address.
+            SWWAF_WAF_MODE: detect
+        volumes:
+            - servewaf-state:/var/lib/smallwebwaf
+        networks:
+            - shared
+        logging: *logging
+        restart: unless-stopped
+
+networks:
+    # The network traefik and Gitea share. Its containers get addresses in its
+    # upper half, which servewaf lets skip the checks. The gateway, the host's
+    # own address on it, stays out of that half: requests docker passes on from
+    # a published port, such as those of visitors over IPv6, can come from it.
+    shared:
+        ipam:
+            config:
+                - subnet: 10.99.0.0/24
+                  ip_range: 10.99.0.128/25
+                  gateway: 10.99.0.1
+
+volumes:
+    gitea-data:
+    servewaf-state: