fix(loaders): retire mootdx from the default A-share chain and health canary

TDX quote servers stopped answering the client protocol mootdx/tdxpy
speak (2026-07, mootdx/mootdx#157): every kline category, market and
server returns empty, realtime quotes return zero rows, and get_k_data
dies on a KeyError inside mootdx. Upstream has been dormant since 2024,
and the weekly health lane has been red on mootdx since it started.

Each auto-mode fetch still spent ~9.5s inside mootdx before falling
through to eastmoney, so the dead slot was pure latency tax on every
A-share call.

Drop mootdx from FALLBACK_CHAINS["a_share"] and from the canary set
(tracked under EXCLUDED_PUBLIC_SOURCES with the upstream issue as the
reason). The loader stays registered: explicit source="mootdx" calls
keep working if a compatible fork ever restores the protocol. Docs
(en/zh/ja/ko/es/ar/id), tool schema hints, env examples and the
data-routing/mootdx skills updated to match.

Closes #1729

Signed-off-by: Yufeng He <40085740+he-yufeng@users.noreply.github.com>

.github/workflows/loader-health.yml

@@ -23,8 +23,8 @@ jobs:
           python-version: '3.11'
           cache: pip
       - name: Install isolated public-source dependencies
-        # mootdx requires an older httpx than the application; do not install
-        # these optional SDKs into the application's dependency environment.
+        # These optional SDKs are pinned tighter than the application's stack;
+        # do not install them into the application's dependency environment.
         run: |
           python -m venv "$RUNNER_TEMP/loader-health-venv"
           "$RUNNER_TEMP/loader-health-venv/bin/python" -m pip install -r tools/requirements-loader-health.txt