fix: remove console.error from graceful error handlers

Removed console.error calls from error handlers that gracefully skip
problematic files and continue processing. These handlers catch errors
when reading or parsing files but successfully return fallback values,
so logging errors creates unnecessary noise during testing and deployment.

Changes:
- vault-tools.ts: Remove console.error from search and frontmatter extraction
- search-utils.ts: Remove console.error from file search handlers
- waypoint-utils.ts: Remove console.error from file read handler
- frontmatter-utils.ts: Remove console.error from YAML and Excalidraw parsing

Test updates:
- Remove test assertions checking for console.error calls since these
  are no longer emitted by graceful error handlers

All 709 tests pass with no console noise during error handling.

src/tools/vault-tools.ts

@@ -342,7 +342,6 @@ export class VaultTools {
 			}
 		} catch (error) {
 			// If frontmatter extraction fails, just return base metadata
-			console.error(`Failed to extract frontmatter for ${file.path}:`, error);
 		}
 
 		return baseMetadata;
@@ -685,7 +684,6 @@ export class VaultTools {
 					}
 				} catch (error) {
 					// Skip files that can't be read
-					console.error(`Failed to search file ${file.path}:`, error);
 				}
 			}