fix(agents): harden Cloud Code Assist compatibility

- Expand schema scrubber to strip additional constraint keywords rejected
  by Cloud Code Assist (examples, minLength, maxLength, minimum, maximum,
  multipleOf, pattern, format, minItems, maxItems, uniqueItems,
  minProperties, maxProperties)
- Extend tool call ID sanitization to cover toolUse and toolCall block
  types (previously only functionCall was sanitized)
- Update pi-tools test to include 'examples' in unsupported keywords

Fixes 400 errors when using google-antigravity/claude-opus-4-5-thinking:
- tools.N.custom.input_schema: JSON schema is invalid
- messages.N.content.N.tool_use.id: String should match pattern

src/agents/pi-embedded-helpers.ts

@@ -146,18 +146,20 @@ export async function sanitizeSessionMessagesImages(
         // Also sanitize tool call IDs in assistant messages (function call blocks)
         const sanitizedContent = await Promise.all(
           filteredContent.map(async (block) => {
-            if (
-              block &&
-              typeof block === "object" &&
-              (block as { type?: unknown }).type === "functionCall" &&
-              (block as { id?: unknown }).id
-            ) {
-              const functionBlock = block as { type: string; id: string };
+            if (!block || typeof block !== "object") return block;
+
+            const type = (block as { type?: unknown }).type;
+            const id = (block as { id?: unknown }).id;
+            if (typeof id !== "string" || !id) return block;
+
+            // Cloud Code Assist tool blocks require ids matching ^[a-zA-Z0-9_-]+$.
+            if (type === "functionCall" || type === "toolUse" || type === "toolCall") {
               return {
-                ...functionBlock,
-                id: sanitizeToolCallId(functionBlock.id),
+                ...((block as unknown) as Record<string, unknown>),
+                id: sanitizeToolCallId(id),
               };
             }
+
             return block;
           }),
         );