Try to fix Snap.

Thanks to xet7 !

docs/Platforms/FOSS/Snap/Snap-build.md

@@ -0,0 +1,103 @@
+# Building the Wekan snap without timeouts
+
+This guide focuses on macOS hosts (Multipass VM) and common timeout fixes. It also applies to Linux hosts with LXD.
+
+## Quick options
+
+- Fastest: use Canonical builders (no local VM)
+
+  ```zsh
+  # One-time: login to the store (required for remote-build)
+  snapcraft login
+  
+  # Build for amd64 on Canonical builders
+  snapcraft remote-build --build-for=amd64
+  ```
+
+- Local VM (macOS + Multipass): increase resources and build verbosely
+
+  ```zsh
+  # Give the builder more CPU/RAM/disk to avoid sluggish downloads
+  export SNAPCRAFT_BUILD_ENVIRONMENT=hosted-multipass
+  export SNAPCRAFT_BUILD_ENVIRONMENT_CPU=4
+  export SNAPCRAFT_BUILD_ENVIRONMENT_MEMORY=8G
+  export SNAPCRAFT_BUILD_ENVIRONMENT_DISK=40G
+  
+  # Clean previous state and build
+  snapcraft clean
+  snapcraft --verbose --debug
+  ```
+
+## What changed to reduce timeouts
+
+- Downloads in `wekan` part now retry with exponential backoff.
+- `caddy` part now attempts APT with retries and falls back to a static binary from the official GitHub release if APT is slow or unreachable.
+
+These changes make the build resilient to transient network issues and slow mirrors.
+
+## Diagnosing where it stalls
+
+- Run a single step for a part to reproduce:
+  ```zsh
+  snapcraft pull wekan -v
+  snapcraft build wekan -v
+  ```
+- Drop into the build environment when it fails:
+  ```zsh
+  snapcraft --debug
+  # Then run the failing commands manually
+  ```
+
+## Tips for macOS + Multipass
+
+- Check networking:
+  ```zsh
+  multipass list
+  multipass exec snapcraft-*-wekan -- ping -c2 github.com
+  ```
+- If the instance looks wedged, recreate it:
+  ```zsh
+  snapcraft clean --use-lxd || true   # harmless on macOS
+  snapcraft clean --step pull
+  multipass delete --purge $(multipass list | awk '/snapcraft-/{print $1}')
+  snapcraft --verbose
+  ```
+
+## Linux hosts (optional)
+
+On Linux, using LXD is often faster and more reliable than Multipass:
+
+```bash
+sudo snap install lxd --channel=5.21/stable
+newgrp lxd
+snapcraft --use-lxd -v
+```
+
+## Common environment knobs
+
+- Proxy/mirror environments inside the build VM if needed:
+  ```zsh
+  export http_proxy=http://proxy.example:3128
+  export https_proxy=$http_proxy
+  export SNAPCRAFT_PROXY_HTTP=$http_proxy
+  export SNAPCRAFT_PROXY_HTTPS=$https_proxy
+  ```
+
+- Speed up apt by pinning retries (already set in the recipe) or switching to a closer mirror by customizing sources in an override if needed.
+
+## Cleaning up caches
+
+If repeated attempts keep hitting corrupt downloads, clean Snapcraft caches:
+
+```zsh
+snapcraft clean --destructive-mode || true
+rm -rf ~/.cache/snapcraft/*
+```
+
+## Reporting
+
+If you still hit timeouts, capture and share:
+- The exact step (pull/build/stage/prime) and part name
+- Output of `snapcraft --verbose --debug`
+- Host OS and Snapcraft version: `snapcraft --version`
+- Multipass resources: `multipass list`