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/features/hook-message-injector/injector.ts

@@ -2,6 +2,7 @@ import { existsSync, mkdirSync, readFileSync, readdirSync, writeFileSync } from
 import { join } from "node:path"
 import { MESSAGE_STORAGE, PART_STORAGE } from "./constants"
 import type { MessageMeta, OriginalMessageContext, TextPart, ToolPermission } from "./types"
+import { log } from "../../shared/logger"
 
 export interface StoredMessage {
   agent?: string
@@ -117,7 +118,7 @@ export function injectHookMessage(
 ): boolean {
   // Validate hook content to prevent empty message injection
   if (!hookContent || hookContent.trim().length === 0) {
-    console.warn("[hook-message-injector] Attempted to inject empty hook content, skipping injection", {
+    log("[hook-message-injector] Attempted to inject empty hook content, skipping injection", {
       sessionID,
       hasAgent: !!originalMessage.agent,
       hasModel: !!(originalMessage.model?.providerID && originalMessage.model?.modelID)