fix(mcplocal): name tools in wire form in gate and favourite-index prose

Follow-up to #124: the boundary WireNameCodec serves underscore-joined
names, but the gate plugin's tool inventories (initialize instructions and
begin_session response) still listed canonical `server/tool`, and the
favourite-index instruction told the model to prefer `favourite/<tool>` —
prose naming functions the model cannot call. Inventories now run through
sanitizeWireName and the instruction describes the favourite_/all_ prefixes.

Cosmetic for routing (slash names still pass through the codec) but
load-bearing for tool selection: models copy names out of prose.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01JaFvfHrQyUKCGv6o3N2Wir

src/mcplocal/tests/router-gate.test.ts

@@ -525,8 +525,11 @@ describe('McpRouter gating', () => {
       );
 
       const result = res.result as { instructions: string };
-      expect(result.instructions).toContain('ha/get_entities');
-      expect(result.instructions).toContain('node-red/get_flows');
+      // Wire form: prose must name what the client can actually call — the
+      // boundary WireNameCodec serves underscore-joined names.
+      expect(result.instructions).toContain('ha_get_entities');
+      expect(result.instructions).toContain('node-red_get_flows');
+      expect(result.instructions).not.toContain('ha/get_entities');
       expect(result.instructions).toContain('after begin_session');
       // Descriptions should NOT be in init instructions (names only)
       expect(result.instructions).not.toContain('Get all entities');
@@ -544,7 +547,9 @@ describe('McpRouter gating', () => {
       );
 
       const text = (res.result as { content: Array<{ text: string }> }).content[0]!.text;
-      expect(text).toContain('ha/get_entities');
+      // Wire form in the inventory (see the initialize-instructions test).
+      expect(text).toContain('ha_get_entities');
+      expect(text).not.toContain('ha/get_entities');
       expect(text).not.toContain('Get all entities');
     });