Replace single large build cache with separate dependencies and incremental
caches. Dependencies cache survives source code changes and uses tiered
restore keys. Removes build directory from caching to improve CI performance
while maintaining effective compilation caching with sccache.
Replace hashFiles('**/package-lock.json') with node_version since wrangler
is installed via npm without a lockfile to hash. Removes trailing dash from
cache keys and ensures npm dependencies are regenerated when Node.js version
changes.
Replace local detect-runner-os action with external detect-versions@v1 to
reduce custom action maintenance. Add architecture detection for future
cross-platform support and namespace all cache keys with "continuwuity-"
prefix to prevent collisions with other projects on shared runners.
Updates cache mount IDs in Dockerfiles to match the new namespacing
convention, ensuring consistent cache isolation across CI and Docker builds.
