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/pr-build/SKILL.md

@@ -19,7 +19,7 @@ tea pr checkout <number>
 If already on a PR branch, verify with:
 ```bash
 git branch --show-current
-git log main..HEAD --oneline
+git log dev..HEAD --oneline
 ```
 
 ### Step 2: Clean build
@@ -39,17 +39,13 @@ If the PR touches threading, memory management, or network code, also build with
 ```bash
 # AddressSanitizer
 rm -rf build-asan
-cmake -B build-asan -S . \
-  -DCMAKE_C_FLAGS="-fsanitize=address -fno-omit-frame-pointer -g" \
-  -DCMAKE_EXE_LINKER_FLAGS="-fsanitize=address"
+cmake -B build-asan -S . -DSANITIZER=address
 cmake --build build-asan -j$(nproc)
 ./build-asan/tests
 
 # ThreadSanitizer (if threading changes)
 rm -rf build-tsan
-cmake -B build-tsan -S . \
-  -DCMAKE_C_FLAGS="-fsanitize=thread -g" \
-  -DCMAKE_EXE_LINKER_FLAGS="-fsanitize=thread"
+cmake -B build-tsan -S . -DSANITIZER=thread
 cmake --build build-tsan -j$(nproc)
 ./build-tsan/tests
 ```
@@ -91,10 +87,10 @@ If tests fail:
 ### Step 6: Run integration tests (optional)
 
 ```bash
-python3 test.py
+python3 -m pytest tests/integration/ -n 4 --dist=load -m "not setpriv"
 ```
 
-This runs the integration + benchmark suite. It takes longer — only run if the user asks or if unit tests pass.
+This runs the integration suite (benchmarking is `benchmark/bench.py`). It takes longer — only run if the user asks or if unit tests pass.
 
 ### Step 7: Fix and commit