Fix: Support path and filePath parameters in message send action

The message tool accepts path and filePath parameters in its schema,
but these were never converted to mediaUrl, causing local files to
be ignored when sending messages.

Changes:
- src/agents/tools/message-tool.ts: Convert path/filePath to media with file:// URL
- src/infra/outbound/message-action-runner.ts: Allow hydrateSendAttachmentParams for "send" action

Fixes issue where local audio files (and other media) couldn't be sent
via the message tool with the path parameter.

Users can now use:
  message({ path: "/tmp/file.ogg" })
  message({ filePath: "/tmp/file.ogg" })

src/agents/tools/message-tool.ts

@@ -340,6 +340,16 @@ export function createMessageTool(options?: MessageToolOptions): AnyAgentTool {
       const action = readStringParam(params, "action", {
         required: true,
       }) as ChannelMessageActionName;
+
+      // Handle path and filePath parameters: convert to media with file:// URL
+      if (action === "send" && !params.media) {
+        const filePath =
+          (params.path as string | undefined) || (params.filePath as string | undefined);
+        if (filePath) {
+          params.media = filePath.startsWith("file://") ? filePath : `file://${filePath}`;
+        }
+      }
+
       const accountId = readStringParam(params, "accountId") ?? agentAccountId;
 
       const gateway = {

src/infra/outbound/message-action-runner.ts

@@ -343,7 +343,7 @@ async function hydrateSendAttachmentParams(params: {
   action: ChannelMessageActionName;
   dryRun?: boolean;
 }): Promise<void> {
-  if (params.action !== "sendAttachment") return;
+  if (params.action !== "sendAttachment" && params.action !== "send") return;
 
   const mediaHint = readStringParam(params.args, "media", { trim: false });
   const fileHint =