A single unresolvable view in the search results (e.g. a view with a
disconnected source) caused the catalog-by-path lookup to return HTTP 400,
which propagated through asyncio.gather and failed the entire
SearchTableAndViews tool call.

get_schemas now isolates per-path failures and returns the error message
alongside each schema. SearchTableAndViews surfaces the affected paths in
a `skipped` field plus a human-readable `skipped_note`, so the user sees
the healthy results and a clear explanation for the ones that were
dropped.

Also adds CLAUDE.md with project context and development guidelines to
help Claude Code sessions work more effectively in this repo.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

- Replace the untyped `Tuple[Dict, Optional[str]]` return of
  `get_schemas` with a `SchemaResult` Pydantic model (`data`, `error`).
  Gives callers named fields and a shape that can be extended without
  another signature change.
- Fix `get_descriptions`: the original silent-drop-on-success was the
  actual root cause of DX-118395 (a broken VDS whose parent PDS was
  deleted tanked the entire call via asyncio.gather). It now tolerates
  per-path failures, logs each via structlog, and continues with the
  paths that resolved.
- Log skipped paths in `get_search_results` via structlog
  (`search_schema_fetch_failed`) before recording them in `skipped`, so
  operators see the failures in logs during an incident.
- Clean up imports: move `logger = log.logger(__name__)` below all
  `from ... import` lines in both `catalog.py` and `search.py`, and
  drop the now-unused `arbitrary_types_allowed` from `SchemaResult`.
- Update tests to the new `SchemaResult` attribute access.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

…r and DataFrame workflow