Implement backend tree search API with frontend integration for real-time sidebar filtering with highlighted matches and vault-scoped results

backend/main.py

@@ -17,6 +17,7 @@ from backend.indexer import (
     reload_index,
     index,
     get_vault_data,
+    get_vault_names,
     find_file_in_index,
     parse_markdown_file,
     _extract_tags,
@@ -120,10 +121,20 @@ class TagsResponse(BaseModel):
     tags: Dict[str, int]
 
 
-class ReloadResponse(BaseModel):
-    """Index reload confirmation with per-vault stats."""
-    status: str
-    vaults: Dict[str, Any]
+class TreeSearchResult(BaseModel):
+    """A single tree search result item."""
+    vault: str
+    path: str
+    name: str
+    type: str = Field(description="'file' or 'directory'")
+    matched_path: str
+
+
+class TreeSearchResponse(BaseModel):
+    """Tree search response with matching paths."""
+    query: str
+    vault_filter: str
+    results: List[TreeSearchResult]
 
 
 class HealthResponse(BaseModel):
@@ -588,6 +599,74 @@ async def api_tags(vault: Optional[str] = Query(None, description="Vault filter"
     return {"vault_filter": vault, "tags": tags}
 
 
+@app.get("/api/tree-search", response_model=TreeSearchResponse)
+async def api_tree_search(
+    q: str = Query("", description="Search query"),
+    vault: str = Query("all", description="Vault filter"),
+):
+    """Search for files and directories in the tree structure.
+    
+    Searches through the file index for matching paths, returning
+    both files and their parent directories that match the query.
+    
+    Args:
+        q: Search string to match against file/directory paths.
+        vault: Vault name or "all" to search everywhere.
+        
+    Returns:
+        ``TreeSearchResponse`` with matching paths and their parent directories.
+    """
+    if not q:
+        return {"query": q, "vault_filter": vault, "results": []}
+    
+    query_lower = q.lower()
+    results = []
+    seen_paths = set()  # Avoid duplicates
+    
+    vaults_to_search = [vault] if vault != "all" else list(index.keys())
+    
+    for vault_name in vaults_to_search:
+        vault_data = get_vault_data(vault_name)
+        if not vault_data:
+            continue
+            
+        vault_root = Path(vault_data["path"])
+        if not vault_root.exists():
+            continue
+        
+        for fpath in vault_root.rglob("*"):
+            if fpath.name.startswith("."):
+                continue
+
+            try:
+                rel_path = str(fpath.relative_to(vault_root)).replace("\\", "/")
+                path_lower = rel_path.lower()
+                name_lower = fpath.name.lower()
+
+                if query_lower not in name_lower and query_lower not in path_lower:
+                    continue
+
+                entry_type = "directory" if fpath.is_dir() else "file"
+                entry_key = f"{vault_name}:{entry_type}:{rel_path}"
+                if entry_key in seen_paths:
+                    continue
+
+                seen_paths.add(entry_key)
+                results.append({
+                    "vault": vault_name,
+                    "path": rel_path,
+                    "name": fpath.name,
+                    "type": entry_type,
+                    "matched_path": rel_path,
+                })
+            except PermissionError:
+                continue
+            except Exception:
+                continue
+    
+    return {"query": q, "vault_filter": vault, "results": results}
+
+
 @app.get("/api/index/reload", response_model=ReloadResponse)
 async def api_reload():
     """Force a full re-index of all configured vaults.