chore(opencode): fix drifted agent/skill docs and repo hygiene

The agent and skill definitions had drifted badly from the current
codebase and tooling, repeating the same class of bug as the benchmark
tool (references to nonexistent scripts and invented flags):

- Replace the removed `python3 test.py` with the real integration
  command (`python3 -m pytest tests/integration/ -n 4 --dist=load
  -m "not setpriv"`) across agents and skills.
- Fix `feature-scout`'s fabricated CLI flag list (--host, --server-mode,
  --use-* etc.) using the authoritative src/client/usage.c flags.
- Fix `perf-analyst` benchmark flags (-m -c -> -j -z) and point at
  benchmark/bench.py instead of stale numbers.
- Correct `code-explainer` (no getopt_long; --sendfile not -f) and
  version drift in the release skill (1.1.0 -> 2.20.0).
- Replace GitHub/`gh` workflows with Gitea/`tea` (PRs target dev; issues
  via tea; branch strategy updated in all agents).
- Use the built-in `-DSANITIZER=address|thread` CMake option instead of
  hand-rolled -fsanitize flags.
- Add `-p 8080 --allow-unauthenticated` to plain-TCP server examples.
- Merge the redundant security-screener into security-auditor; drop the
  duplicate (16 agents remain).

Repo hygiene: gitignore `root/` and `test_partial_install_tmp/`, remove
the empty leftover trees, delete the tracked scratch scripts tmux.sh and
to_one_file.py, and note the compile_commands.json symlink in README.

.opencode/skills/debug-workflow/SKILL.md

@@ -32,23 +32,19 @@ Try to reproduce the issue with the exact command the user provides.
 
 **Memory errors (first priority):**
 ```bash
-rm -rf build
-cmake -B build -S . \
-  -DCMAKE_C_FLAGS="-fsanitize=address -fno-omit-frame-pointer -g" \
-  -DCMAKE_EXE_LINKER_FLAGS="-fsanitize=address"
-cmake --build build -j$(nproc)
-./build/tests
+rm -rf build-asan
+cmake -B build-asan -S . -DSANITIZER=address
+cmake --build build-asan -j$(nproc)
+./build-asan/tests
 # or run the failing command
 ```
 
 **Thread errors:**
 ```bash
-rm -rf build
-cmake -B build -S . \
-  -DCMAKE_C_FLAGS="-fsanitize=thread -g" \
-  -DCMAKE_EXE_LINKER_FLAGS="-fsanitize=thread"
-cmake --build build -j$(nproc)
-./build/tests
+rm -rf build-tsan
+cmake -B build-tsan -S . -DSANITIZER=thread
+cmake --build build-tsan -j$(nproc)
+./build-tsan/tests
 ```
 
 **Valgrind (if ASan doesn't find it):**
@@ -108,13 +104,12 @@ cmake -B build -S . && cmake --build build -j$(nproc)
 ./build/tests
 
 # If integration test needed
-python3 test.py
+python3 -m pytest tests/integration/ -n 4 --dist=load -m "not setpriv"
 
 # Re-run under sanitizer to confirm fix
-rm -rf build
-cmake -B build -S . -DCMAKE_C_FLAGS="-fsanitize=address -fno-omit-frame-pointer" \
-  -DCMAKE_EXE_LINKER_FLAGS="-fsanitize=address"
-cmake --build build -j$(nproc)
+rm -rf build-asan
+cmake -B build-asan -S . -DSANITIZER=address
+cmake --build build-asan -j$(nproc)
 # reproduce the original failing command
 ```