feat: datasheet tools + fix missing delete_schematic_component

New tools - datasheet:
- get_datasheet_url: construct LCSC datasheet PDF URL + product page URL
  without any API key (URL schema: https://www.lcsc.com/datasheet/<C#>.pdf)
- enrich_datasheets: scan .kicad_sch, write LCSC datasheet URL into every
  symbol that has an LCSC property but an empty Datasheet field; supports
  dry_run=true for preview; text-based implementation (no skip writes)
  Implementation: python/commands/datasheet_manager.py

New tool - schematic:
- delete_schematic_component: remove a placed symbol from a .kicad_sch file
  by reference designator (e.g. R1, U3)

Bug fix - delete_schematic_component (two separate root causes):
1. No MCP tool named delete_schematic_component was registered at all.
   Any delete-symbol request fell through to the PCB-only delete_component
   tool which searches pcbnew.BOARD and always returned 'Component not found'
   for schematic symbols.
2. component_schematic.py::remove_component() still used skip for writes.
   PR #40 rewrote DynamicSymbolLoader (add path) to avoid skip-induced
   schematic corruption, but the delete path was not touched by that PR.

Fix: _handle_delete_schematic_component in kicad_interface.py uses direct
text manipulation with parenthesis-depth tracking (same technique as PR #40),
bypassing component_schematic.py entirely. Error message explicitly guides
users: 'use delete_component for PCB footprints'.

Files changed:
- python/commands/datasheet_manager.py (new)
- src/tools/datasheet.ts (new)
- python/kicad_interface.py: 3 new handlers + dispatch entries
- src/tools/schematic.ts: delete_schematic_component tool
- src/server.ts: registerDatasheetTools import + call
- src/tools/index.ts: export registerDatasheetTools
- CHANGELOG.md: document all above

src/server.ts

@@ -21,6 +21,7 @@ import { registerSchematicTools } from "./tools/schematic.js";
 import { registerLibraryTools } from "./tools/library.js";
 import { registerSymbolLibraryTools } from "./tools/library-symbol.js";
 import { registerJLCPCBApiTools } from "./tools/jlcpcb-api.js";
+import { registerDatasheetTools } from "./tools/datasheet.js";
 import { registerUITools } from "./tools/ui.js";
 import { registerRouterTools } from "./tools/router.js";
 
@@ -241,6 +242,7 @@ export class KiCADMcpServer {
     registerLibraryTools(this.server, this.callKicadScript.bind(this));
     registerSymbolLibraryTools(this.server, this.callKicadScript.bind(this));
     registerJLCPCBApiTools(this.server, this.callKicadScript.bind(this));
+    registerDatasheetTools(this.server, this.callKicadScript.bind(this));
     registerUITools(this.server, this.callKicadScript.bind(this));
 
     // Register all resources