feat(ai): integrate GeminiCliAdapter into ai_client

gemini_cli_adapter.py

@@ -0,0 +1,62 @@
+import subprocess
+import json
+import sys
+
+class GeminiCliAdapter:
+    def __init__(self, binary_path="gemini"):
+        self.binary_path = binary_path
+        self.last_usage = None
+        self.session_id = None
+
+    def send(self, message):
+        """
+        Sends a message to the Gemini CLI and processes the streaming JSON output.
+        """
+        command = [self.binary_path, 'run', message, '--output-format', 'stream-json']
+        if self.session_id:
+            command.extend(['--resume', self.session_id])
+
+        accumulated_text = ""
+        
+        # Using subprocess.Popen as requested
+        process = subprocess.Popen(
+            command,
+            stdout=subprocess.PIPE,
+            text=True
+        )
+
+        try:
+            # Read stdout line by line
+            for line in process.stdout:
+                line = line.strip()
+                if not line:
+                    continue
+
+                try:
+                    data = json.loads(line)
+                    msg_type = data.get("type")
+
+                    if msg_type == "message":
+                        # Append message text to results
+                        accumulated_text += data.get("text", "")
+
+                    elif msg_type == "result":
+                        # Capture final usage and session persistence
+                        self.last_usage = data.get("usage")
+                        self.session_id = data.get("session_id")
+
+                    elif msg_type in ("status", "tool_use"):
+                        # Log status/tool_use to stderr for debugging
+                        sys.stderr.write(f"GeminiCliAdapter [{msg_type}]: {line}\n")
+                        sys.stderr.flush()
+
+                except json.JSONDecodeError:
+                    # Skip lines that are not valid JSON
+                    continue
+
+            process.wait()
+        except Exception as e:
+            process.kill()
+            raise e
+
+        return accumulated_text