feat(web): add Brave Search (free tier) and DDGS search providers

Both implement WebSearchProvider via tools/web_providers/ — matching the
existing SearXNG pattern (PR #5c906d702). Search-only; pair with any
extract provider via web.extract_backend.

- tools/web_providers/brave_free.py — Brave Search API (free tier, 2k
  queries/mo). Uses BRAVE_SEARCH_API_KEY as X-Subscription-Token.
- tools/web_providers/ddgs.py — DuckDuckGo via the ddgs Python package.
  No API key; gated on package importability.
- tools/web_tools.py: both backends added to _get_backend() config list
  and auto-detect chain (trails paid providers), _is_backend_available,
  web_search_tool dispatch, web_extract_tool + web_crawl_tool search-only
  refusals, check_web_api_key, and the __main__ diagnostic. Introduces
  _ddgs_package_importable() helper so tests can monkeypatch a single
  symbol for the ddgs availability check.
- hermes_cli/tools_config.py: picker entries for both providers; ddgs
  gets a post_setup handler that runs `pip install ddgs`.
- hermes_cli/config.py: BRAVE_SEARCH_API_KEY in OPTIONAL_ENV_VARS.
- scripts/release.py: AUTHOR_MAP entry for @Abd0r.
- tests: 14 new tests (brave-free) + 15 new tests (ddgs) covering
  provider unit behavior, backend wiring, and search-only refusals.

Salvages the brave-free + ddgs portion of PR #19796. Not included: the
in-line helpers in web_tools.py (replaced with provider modules to match
the shipped architecture), the lynx-based extract path (these backends
should refuse extract with a clear error — users pair with a real
extract provider), and scripts/start-llama-server.sh (unrelated).

Co-authored-by: Abd0r <223003280+Abd0r@users.noreply.github.com>

tools/web_providers/ddgs.py

@@ -0,0 +1,98 @@
+"""DuckDuckGo web search provider via the ``ddgs`` Python package.
+
+DuckDuckGo does not provide an official programmatic search API.  The
+community-maintained `ddgs <https://pypi.org/project/ddgs/>`_ package (the
+renamed successor of ``duckduckgo-search``) scrapes DuckDuckGo's HTML results
+page and normalizes them.  It implements ``WebSearchProvider`` only — there is
+no extract capability.
+
+Configuration::
+
+    # No API key required. Enable by installing the package and pointing the
+    # web backend at ddgs:
+    pip install ddgs
+
+    # ~/.hermes/config.yaml
+    web:
+      search_backend: "ddgs"
+      extract_backend: "firecrawl"    # pair with an extract provider if needed
+
+Rate limits are enforced server-side by DuckDuckGo.  Expect intermittent
+``DuckDuckGoSearchException`` / 202 responses under heavy use; this provider
+surfaces them as ``{"success": False, "error": ...}`` rather than crashing
+the tool call.
+
+See https://duckduckgo.com/?q=duckduckgo+tos for terms of use.
+"""
+
+from __future__ import annotations
+
+import logging
+from typing import Any, Dict
+
+from tools.web_providers.base import WebSearchProvider
+
+logger = logging.getLogger(__name__)
+
+
+class DDGSSearchProvider(WebSearchProvider):
+    """Search via the ``ddgs`` package (DuckDuckGo HTML scrape).
+
+    No API key required.  The provider is considered "configured" when the
+    ``ddgs`` package is importable — there is nothing else to set up.
+    """
+
+    def provider_name(self) -> str:
+        return "ddgs"
+
+    def is_configured(self) -> bool:
+        """Return True when the ``ddgs`` package is importable.
+
+        Called at tool-registration time; must not perform network I/O.
+        """
+        try:
+            import ddgs  # noqa: F401
+            return True
+        except ImportError:
+            return False
+
+    def search(self, query: str, limit: int = 5) -> Dict[str, Any]:
+        """Execute a DuckDuckGo search and return normalized results.
+
+        Returns ``{"success": True, "data": {"web": [...]}}`` on success or
+        ``{"success": False, "error": str}`` on failure (missing package,
+        rate-limited, network error, etc.).
+        """
+        try:
+            from ddgs import DDGS  # type: ignore
+        except ImportError:
+            return {
+                "success": False,
+                "error": "ddgs package is not installed — run `pip install ddgs`",
+            }
+
+        # DDGS().text yields at most `max_results` items; we cap defensively
+        # in case the package ignores the hint.
+        safe_limit = max(1, int(limit))
+
+        try:
+            web_results = []
+            with DDGS() as client:
+                for i, hit in enumerate(client.text(query, max_results=safe_limit)):
+                    if i >= safe_limit:
+                        break
+                    url = str(hit.get("href") or hit.get("url") or "")
+                    web_results.append(
+                        {
+                            "title": str(hit.get("title", "")),
+                            "url": url,
+                            "description": str(hit.get("body", "")),
+                            "position": i + 1,
+                        }
+                    )
+        except Exception as exc:  # noqa: BLE001 — ddgs raises its own exceptions
+            logger.warning("DDGS search error: %s", exc)
+            return {"success": False, "error": f"DuckDuckGo search failed: {exc}"}
+
+        logger.info("DDGS search '%s': %d results (limit %d)", query, len(web_results), limit)
+        return {"success": True, "data": {"web": web_results}}