feat: upgrade pi-ai to 0.70.0 and add gpt-5.5 filter rules

Bump @mariozechner/pi-ai from ^0.68.1 to 0.70.0. Add gpt-5.5 to the
request filter rules for both github-copilot and openai-codex providers
(stripping temperature, matching the gpt-5.4 pattern). Also add gpt-5.5
to the vitest setup mock for openai-codex.

Author: mcowger

bun.lock

@@ -16,7 +16,7 @@
     "@fastify/multipart": "^10.0.0",
     "@fastify/static": "^9.1.3",
     "@google/genai": "^1.50.1",
-    "@mariozechner/pi-ai": "^0.68.1",
+    "@mariozechner/pi-ai": "0.70.0",
     "@plexus/shared": "workspace:*",
     "@sinclair/typebox": "^0.34.49",
     "dotenv": "^17.4.2",

packages/backend/package.json

@@ -13,6 +13,12 @@ export const PI_AI_REQUEST_FILTERS: PiAiRequestFilterRule[] = [
     strippedParameters: ['temperature'],
     comment: 'GitHub Copilot rejects temperature for this model.',
   },
+  {
+    provider: 'github-copilot',
+    model: 'gpt-5.5',
+    strippedParameters: ['temperature'],
+    comment: 'GitHub Copilot rejects temperature for this model.',
+  },
   {
     provider: 'github-copilot',
     model: 'gpt-5.2-codex',
@@ -43,6 +49,12 @@ export const PI_AI_REQUEST_FILTERS: PiAiRequestFilterRule[] = [
     strippedParameters: ['temperature'],
     comment: 'Codex OAuth rejects temperature for this model.',
   },
+  {
+    provider: 'openai-codex',
+    model: 'gpt-5.5',
+    strippedParameters: ['temperature'],
+    comment: 'Codex OAuth rejects temperature for this model.',
+  },
   {
     provider: 'openai-codex',
     model: 'gpt-5.2-codex',

packages/backend/src/filters/pi-ai-request-filter-rules.ts

@@ -100,7 +100,7 @@ const mockLogger = {
 //     them; re-apply implementations in beforeEach because mockReset: true
 //     wipes vi.fn() state between tests.
 //   • getModels returns all known test models so quota-error assertions that
-//     validate gpt-5.4 is valid for openai-codex always pass.
+//     validate gpt-5.4/gpt-5.5 are valid for openai-codex always pass.
 //   • getModel always includes the `api` field — OAuthTransformer.executeRequest
 //     dispatches on model.api and crashes with "No API provider registered"
 //     if it is missing.
@@ -117,6 +117,13 @@ vi.mock('@mariozechner/pi-ai', () => ({
           provider: 'openai-codex',
           api: 'openai-codex-responses',
         },
+        {
+          id: 'gpt-5.5',
+          name: 'GPT-5.5',
+          contextWindow: 128000,
+          provider: 'openai-codex',
+          api: 'openai-codex-responses',
+        },
       ];
     }
     return [