fix: Antigravity API compatibility and Gemini thinking tag leakage (#167)

* fix: ensure type:object in sanitized tool schemas for Antigravity API

The sanitizeSchemaForGoogle function strips unsupported JSON Schema
keywords like anyOf, but this can leave schemas with 'properties' and
'required' fields without a 'type' field. Both Google's Gemini API and
Anthropic via Antigravity require 'type: object' when these fields exist.

This fix adds a post-sanitization check that ensures type is set to
'object' when properties or required fields are present.

Fixes errors like:
- Gemini: 'parameters.properties: only allowed for OBJECT type'
- Anthropic: 'tools.6.custom.input_schema.type: Field required'

* fix: regenerate pi-ai patch with proper pnpm format

The patch now correctly applies via pnpm patch-commit, fixing:
- Thinking blocks: skip for Gemini, send with signature for Claude
- Schema sanitization: ensure type:object after removing anyOf
- Remove strict:null for LM Studio/Antigravity compatibility

Tested with all Antigravity models (Gemini and Claude).

* fix: strip thinking tags from block streaming output to prevent Gemini tag leakage

package.json

@@ -140,8 +140,7 @@
       "@sinclair/typebox": "0.34.46"
     },
     "patchedDependencies": {
-      "@mariozechner/pi-ai": "patches/@mariozechner__pi-ai.patch",
-      "@mariozechner/pi-coding-agent@0.32.3": "patches/@mariozechner__pi-coding-agent@0.32.3.patch"
+      "@mariozechner/pi-ai": "patches/@mariozechner__pi-ai.patch"
     }
   },
   "vitest": {