feat: add tcx and bpf token tutorials (#203)

* feat: add tcx and bpf token tutorials

* docs: auto-generate documentation

* docs: rewrite tcx and bpf_token tutorials with richer content and consistent style

Rewrote all 4 README files (EN/ZH for both tutorials) to match the
existing tutorial style with detailed background, full code listings,
step-by-step explanations, comparison tables, and proper references.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* style: replace em dashes with colons, commas, and parentheses

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* docs: auto-generate documentation

* ci: add tcx and bpf_token builds to CI; simplify execl in token_userns_demo

- Add make targets for src/50-tcx and src/features/bpf_token to the
  test-libbpf CI workflow.
- Replace four separate execl() calls with a single execv() using a
  dynamically built argv array, reducing complexity and eliminating
  CodeFactor command-injection false positives.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* ci: fix mkdocs path in trigger-sync workflow

Use .venv/bin/mkdocs instead of bare mkdocs, since make install
puts it inside a virtualenv.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

---------

Co-authored-by: LinuxDev9002 <linuxdev8883@example.com>
Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

.github/workflows/test-libbpf.yml

@@ -111,3 +111,11 @@ jobs:
     - name: test features bpf_wq
       run: |
           make -C src/features/bpf_wq
+
+    - name: test 50 tcx
+      run: |
+          make -C src/50-tcx
+
+    - name: test features bpf_token
+      run: |
+          make -C src/features/bpf_token