refactor: replace console.log/warn/error with file-based log() for silent logging

Replace all console output with shared logger to write to
/tmp/oh-my-opencode.log instead of stdout/stderr.

Files changed:
- index.ts: console.warn → log()
- hook-message-injector/injector.ts: console.warn → log()
- lsp/client.ts: console.error → log()
- ast-grep/downloader.ts: console.log/error → log()
- session-recovery/index.ts: console.error → log()
- comment-checker/downloader.ts: console.log/error → log()

CLI tools (install.ts, doctor, etc.) retain console output for UX.

src/tools/lsp/client.ts

@@ -11,6 +11,7 @@ import {
 } from "vscode-jsonrpc/node"
 import { getLanguageId } from "./config"
 import type { Diagnostic, ResolvedServer } from "./types"
+import { log } from "../../shared/logger"
 
 interface ManagedClient {
   client: LSPClient
@@ -306,7 +307,7 @@ export class LSPClient {
     })
 
     this.connection.onError((error) => {
-      console.error("LSP connection error:", error)
+      log("LSP connection error:", error)
     })
 
     this.connection.listen()