Enhanced the table filter in the Schema panel to search both table names & column names. When a column matches the search query, the table automatically expands (in-memory only) to show the matching columns.

Changes

• Filter logic: Updated table filtering to include column name matches using existing Redux allColumns data
• Auto-expansion: Tables with matching columns now auto-expand their table row AND columns folder during search
• State management: Search-driven expansions are purely in-memory and never persist to localStorage
• Race condition fix: Added cleanup mechanism (isCancelled flag) to prevent stale async operations from causing incorrect expansion states during rapid input changes

Implementation Details

1. Column matching: Uses allColumns from Redux store (already fetched via information_schema.columns()) - no additional network requests
2. tablesWithColumnMatches Set: Computed via useMemo to track which tables need auto-expansion
3. In-memory expansion: Sets node.isExpanded = true directly on tree nodes without calling setSectionExpanded() (localStorage)
4. Async safety: Effect cleanup function prevents race conditions when user types/deletes rapidly

Behavior

• Search for table name → table stays collapsed (existing behavior preserved)
• Search for column name → table + columns auto-expand, matching columns visible
• Clear search → all expansions revert to localStorage state (user's manual expansions preserved)
• Rapid typing/backspace → no ghost expansions

Testing

Tested with sample tables containing columns like col_string, col_ts, sensor_id:

• Column search correctly expands matching tables
• Table name search maintains collapsed state
• Rapid input (backspace spam) correctly handles state
• Clearing search restores previous expansion states

Closes #363