feat: add footprint + symbol creator tools

Footprint tools:
- create_footprint: generates .kicad_mod via f-string (SMD/THT, courtyard, silkscreen, fab)
- edit_footprint_pad: updates size/position/drill/shape in-place
- list_footprint_libraries: scans .pretty directories
- register_footprint_library: adds entry to fp-lib-table

Symbol tools:
- create_symbol: generates .kicad_sym with pins, rectangles, polylines
- delete_symbol: removes symbol from library
- list_symbols_in_library: lists all symbols in a .kicad_sym file
- register_symbol_library: adds entry to sym-lib-table

Also:
- Fix footprint format version: 20250114 (schematic) -> 20241229 (footprint)
- Two MCP prompts: create_footprint_guide + footprint_ipc_checklist

Live tested: TMC2209 footprint (19 pads), R_0603_Test, edit_footprint_pad,
TMC2209_Custom symbol with pins all confirmed in KiCAD 9

src/prompts/footprint.ts

@@ -0,0 +1,137 @@
+/**
+ * Footprint prompts for KiCAD MCP server
+ *
+ * Guides Claude in creating and editing KiCAD footprints (.kicad_mod)
+ * using the create_footprint, edit_footprint_pad, and list_footprint_libraries tools.
+ */
+
+import { McpServer } from "@modelcontextprotocol/sdk/server/mcp.js";
+import { z } from "zod";
+import { logger } from "../logger.js";
+
+export function registerFootprintPrompts(server: McpServer): void {
+  logger.info("Registering footprint prompts");
+
+  // ------------------------------------------------------
+  // Create Footprint Prompt
+  // ------------------------------------------------------
+  server.prompt(
+    "create_footprint_guide",
+    {
+      component: z
+        .string()
+        .describe(
+          "Component description, e.g. 'SOT-23 NPN transistor' or '2-pin JST XH 2.5mm connector'",
+        ),
+      libraryPath: z
+        .string()
+        .optional()
+        .describe("Target .pretty library path (optional)"),
+    },
+    () => ({
+      messages: [
+        {
+          role: "user",
+          content: {
+            type: "text",
+            text: `You are a KiCAD footprint expert. Create a correct KiCAD 9 footprint using the create_footprint tool.
+
+## Component to footprint
+{{component}}
+
+## Library path
+{{libraryPath}}
+
+## Rules for correct footprints
+
+### Coordinate system
+- Origin (0,0) is the footprint anchor, typically the centre of the pad pattern.
+- X increases to the right, Y increases downward (same as KiCAD screen).
+- All values in millimetres.
+
+### SMD pads
+- type: "smd"
+- Default layers: ["F.Cu", "F.Paste", "F.Mask"]
+- No drill needed.
+- Common shapes: "rect" for square/rectangular, "roundrect" for ICs.
+
+### THT pads
+- type: "thru_hole"
+- Default layers: ["*.Cu", "*.Mask"]
+- drill required (round = scalar, oval = {w, h}).
+- Pad 1 is typically square (rect), remaining pads are circle.
+
+### Courtyard (F.CrtYd)
+- Add 0.25 mm clearance around the outermost extent of pads.
+- Line width: 0.05 mm.
+
+### Silkscreen (F.SilkS)
+- Shows the component body outline, typically slightly inside the courtyard.
+- Line width: 0.12 mm.
+- Must not overlap pads.
+
+### Fab layer (F.Fab)
+- Shows the realistic component outline with pin-1 marker.
+- Line width: 0.10 mm.
+
+### Reference text
+- Place "REF**" above the courtyard (negative Y = above).
+- Value text below the courtyard (positive Y = below).
+
+## Workflow
+1. Calculate pad positions from datasheet pitch and land pattern.
+2. Call create_footprint with pads[], courtyard, silkscreen, fabLayer.
+3. Verify with edit_footprint_pad if any correction is needed.
+
+## Common packages quick reference
+| Package   | Pitch  | Pad size (SMD)   | Notes                        |
+|-----------|--------|------------------|------------------------------|
+| 0402      | 1.0 mm | 0.6 × 0.7 mm     | Very small, min 0.5 mm drill |
+| 0603      | 1.6 mm | 1.0 × 1.0 mm     | Standard small passive       |
+| 0805      | 2.0 mm | 1.4 × 1.2 mm     | Easy to hand-solder          |
+| SOT-23    | 0.95 mm| 1.0 × 1.3 mm     | 3-pin, 2 on one side         |
+| SOT-23-5  | 0.95 mm| 0.6 × 1.0 mm     | 5-pin                        |
+| SOIC-8    | 1.27 mm| 1.6 × 0.6 mm     | 4 pins each side             |
+| DIP-8     | 2.54 mm| dia 1.6, drill 0.8| THT, 100 mil grid            |
+
+Now create the footprint for: {{component}}`,
+          },
+        },
+      ],
+    }),
+  );
+
+  // ------------------------------------------------------
+  // Footprint IPC Checklist Prompt
+  // ------------------------------------------------------
+  server.prompt(
+    "footprint_ipc_checklist",
+    {
+      footprintPath: z
+        .string()
+        .describe("Path to the .kicad_mod file to review"),
+    },
+    () => ({
+      messages: [
+        {
+          role: "user",
+          content: {
+            type: "text",
+            text: `Review the footprint at {{footprintPath}} against IPC-7351 land pattern guidelines.
+
+Check:
+1. **Pad size** – is the copper area sufficient for soldering (not undersized)?
+2. **Courtyard** – at least 0.25 mm clearance around all pads?
+3. **Silkscreen** – does it overlap pads? (it should NOT)
+4. **Pad 1 marker** – is pin 1 identifiable (square pad or triangle on silkscreen)?
+5. **Drill size** – for THT: drill ≥ lead diameter + 0.3 mm?
+6. **Layer assignments** – SMD pads: F.Cu/F.Paste/F.Mask; THT: *.Cu/*.Mask?
+7. **Anchor** – is the origin centred on the pad pattern?
+
+Use edit_footprint_pad to fix any issues found.`,
+          },
+        },
+      ],
+    }),
+  );
+}