Improve web search region selection and normalize provider resultsHEADmain

Update ddgs to 9.16.0 and keep backend="auto" while preserving the
LLM-facing query/max_results inputs and title/href/body result schema.

Implementation:
- Add OLLAMA_WEB_SEARCH_REGION with auto/us-en/jp-jp values, normalized
  configuration input, and a clear startup error for unsupported values.
- In auto mode, detect kana after NFKC normalization and exclusion of URLs
  and site:/filetype: tokens. Select jp-jp for kana and us-en otherwise,
  without modifying the original query or sharing per-call region state.
- Preserve href/url and body/snippet fallbacks and normalize None values.
- Reject malformed HTTP(S) URLs without DNS lookups or extra requests.
- Unwrap known Yahoo redirect URLs before excluding Bing aclick ads.
- Represent missing and URL-only titles as empty strings rather than
  inventing titles from snippets. Preserve remaining provider order and
  allow fewer results after filtering, without additional searches.
- Preserve provider exception propagation and identify ddgs in error logs.

Coverage and documentation:
- Add 72 regression cases for configuration, region routing, concurrency,
  public schemas, title/URL/ad boundaries, limits, and search_and_fetch
  continuation. Update existing provider mocks and log assertions.
- Document the region environment setting and result semantics in both
  READMEs and tools-schema.md; update the changelog.
- Keep only a short backend availability caveat in tools-schema.md and
  remove the temporary backend comparison, design, and validation docs.

Validation:
- pytest: 222 passed; ruff check . and mypy src/ passed.
- uv lock --check and git diff --check passed.
- Initial live acceptance: 56 searches plus 3 registry smoke checks;
  default-region auto succeeded 8/18 times and real ad filtering removed
  two ads. Stable relevance/title quality targets remain unmet because
  provider acquisition is unreliable.
- Follow-up backend study: 234 comparative searches plus 3 Yahoo response
  diagnostics. Yahoo led individual backends at 9/18; restricted multi-
  backend combinations did not outperform the contemporaneous auto
  control. Authentication, access restrictions, temporary upstream
  failures, and Yahoo HTML/parser mismatches were observed.

Do not claim search reliability is fixed or add backend configuration,
custom retries, ranking changes, or challenge bypasses. Running app
processes were not restarted; restart is needed to load the changes.

1 files changed, 13 insertions, 0 deletions

diff --git a/README.md b/README.md
index cb7a62b..7f39b27 100644
--- a/README.md
+++ b/README.md
@@ -79,6 +79,19 @@ ollama-web
 | `OLLAMA_WEB_MCP_STDIO_ALLOWLIST` | Not set | Comma-separated absolute paths of executable files allowed for stdio MCP |
 | `OLLAMA_WEB_MCP_HTTPS_ALLOWLIST` | Not set | Comma-separated hostnames allowed for remote HTTPS MCP connections |
 | `OLLAMA_WEB_LANGUAGE` | `ja` | Display language for the UI and LLM prompts (`ja` or `en`) |
+| `OLLAMA_WEB_SEARCH_REGION` | `auto` | Search region: `auto`, `us-en`, or `jp-jp`. Auto selects Japan for queries containing kana, otherwise the US. |
+
+Search uses ddgs with `backend="auto"`. Region is selected internally; the LLM tool
+still accepts only `query` and `max_results`. Detection normalizes half-width kana
+and ignores URLs and `site:`/`filetype:` tokens, without rewriting the search query.
+Kanji-only queries use `us-en`; set `jp-jp` to prefer Japan for every query. This
+setting is independent of the UI language and takes effect after restarting the app.
+Invalid values stop startup with a configuration error.
+
+Search summaries omit malformed URLs and known Bing ad links, and represent missing
+or URL-only titles as an empty string while keeping the URL and snippet. Filtering
+can reduce the result count; it does not trigger extra requests. Provider failures
+remain tool errors.
 
 ### Multilingual Support