✅ **Issue: Prebuild `quickstart` binary in rust-dev container**

**Description:**
Currently, the `quickstart` CLI binary is built during CI, which adds \~1.5 minute to each run. We should build it as part of the base container to speed up CI and ensure consistency across environments.

**Tasks:**

* [ ] Add `cargo build --release -p quickstart` to the dev container build process
* [ ] Copy resulting binary into a known path (`/usr/local/bin/quickstart`)
* [ ] Update CI to invoke that prebuilt binary if present
* [ ] Test container locally to confirm availability

**Status:** Ready
**Branch:** `prebuild-quickstart`
**Blocks:** N/A
**Blocked By:** N/A
**Related To:** `cr8s/.github/workflows/ci.yml` speedup

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