fix: remove dead try/catch in insertNode and fix SENSITIVE_PATHS case sensitivity

[zichen0116]

Changes

Two small fixes:

1. Remove dead try/catch in QueryBuilder.insertNode()

src/db/queries.ts — The try/catch block around this.stmts.insertNode.run() only re-throws the error, adding no value. Removed it to reduce noise.

- try {
-   this.stmts.insertNode.run({...});
- } catch (error) {
-   throw error;
- }
+ this.stmts.insertNode.run({...});

2. Fix SENSITIVE_PATHS case-sensitivity bug on Windows

src/utils.ts — The SENSITIVE_PATHS Set contained PascalCase entries (C:\Windows) but the comparison used resolved.toLowerCase(), so Windows paths would never match the sensitive path check.

Normalized all entries to lowercase to fix the comparison.

Both fixes are minimal, low-risk code quality improvements.