fix: address PR review issues for schematic analysis tools

Eliminate repeated file parsing by extracting _extract_lib_symbols helper
that walks already-parsed sexp_data once instead of re-reading the file
per symbol via PinLocator. Support diagonal wire overlap detection using
cross-product parallelism and 1D projection. Fix wire region inclusion to
use AABB intersection for pass-through wires. Normalize view region
coordinates. Clarify tolerance docstrings across Python, TS, and schema.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/tools/schematic.ts

@@ -1165,7 +1165,7 @@ Note: operates on .kicad_sch files only. To modify a PCB footprint use edit_comp
     "Detect spatially overlapping symbols, wires, and labels in the schematic. Finds duplicate power symbols at the same position, collinear overlapping wires, and labels stacked on top of each other.",
     {
       schematicPath: z.string().describe("Path to the .kicad_sch schematic file"),
-      tolerance: z.number().optional().describe("Distance in mm below which elements are considered overlapping (default: 0.5)"),
+      tolerance: z.number().optional().describe("Distance threshold in mm for label proximity and wire collinearity checks. Symbol overlap uses bounding-box intersection. (default: 0.5)"),
     },
     async (args: { schematicPath: string; tolerance?: number }) => {
       const result = await callKicadScript("find_overlapping_elements", args);