feat: Better source-aware testing (#391)

docs/integrations/ci-cd.mdx

@@ -13,6 +13,12 @@ Use the `-n` or `--non-interactive` flag:
 strix -n --target ./app --scan-mode quick
 ```
 
+For pull-request style CI runs, Strix automatically scopes quick scans to changed files. You can force this behavior and set a base ref explicitly:
+
+```bash
+strix -n --target ./app --scan-mode quick --scope-mode diff --diff-base origin/main
+```
+
 ## Exit Codes
 
 | Code | Meaning |
@@ -78,3 +84,7 @@ jobs:
 <Note>
 All CI platforms require Docker access. Ensure your runner has Docker available.
 </Note>
+
+<Tip>
+If diff-scope fails in CI, fetch full git history (for example, `fetch-depth: 0` in GitHub Actions) so merge-base and branch comparison can be resolved.
+</Tip>

docs/integrations/github-actions.mdx

@@ -18,6 +18,8 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
 
       - name: Install Strix
         run: curl -sSL https://strix.ai/install | bash
@@ -58,3 +60,7 @@ The workflow fails when vulnerabilities are found:
 <Tip>
 Use `quick` mode for PRs to keep feedback fast. Schedule `deep` scans nightly.
 </Tip>
+
+<Note>
+For pull_request workflows, Strix automatically uses changed-files diff-scope in CI/headless runs. If diff resolution fails, ensure full history is fetched (`fetch-depth: 0`) or set `--diff-base`.
+</Note>