flake: Optimize Nix check inputs and CI smoke tests

Narrow flake source sets for generated parity,
Rust package builds, and CLI formatting to reduce
avoidable invalidation. Factor repeated Bun/Biome
check derivations into shared helpers and preserve
existing public check names and release outputs.

Update PR CI to time Nix validation and smoke-test
the already-built default package binary instead of
invoking separate nix run evaluations.

Co-authored-by: SCE <sce@crocoder.dev>

Author: davidabram

.github/workflows/pr-ci.yml

@@ -41,12 +41,11 @@ jobs:
           use-gha-cache: true
 
       - name: Run flake checks
-        run: nix flake check --print-build-logs
-
-      - name: Build default package
-        run: nix build .#default --print-build-logs
+        run: |
+          time nix flake check --print-build-logs
 
-      - name: Smoke-test CLI
+      - name: Build and smoke-test CLI
         run: |
-          nix run .#sce -- --help
-          nix run .#sce -- version
+          time nix build .#default --out-link result --print-build-logs
+          ./result/bin/sce --help
+          ./result/bin/sce version