fix(openclaw): dedupe postinstall rebuild block (SyntaxError: startMs… already declared) (#1388)

Remove duplicate const startMs/result and keep rebuild only inside the
else branch when native bindings are missing.

## Description

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required for this change.

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## Type of change

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## How Has This Been Tested?

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## Checklist

- [ ] I have performed a self-review of my own code | 我已自行检查了自己的代码
- [ ] I have commented my code in hard-to-understand areas |
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Author: syzsunshine219

apps/memos-local-openclaw/scripts/postinstall.cjs

@@ -397,16 +397,6 @@ if (sqliteBindingsExist()) {
   warn("better-sqlite3 native bindings are missing or not loadable.");
   log(`Searched in: ${DIM}${sqliteModulePath}/build/${RESET}`);
   log("Running: npm rebuild better-sqlite3 (may take 30-60s)...");
-}
-
-const startMs = Date.now();
-
-const result = spawnSync(npmCmd, ["rebuild", "better-sqlite3"], {
-  cwd: pluginDir,
-  stdio: "pipe",
-  shell: false,
-  timeout: 180_000,
-});
 
   const startMs = Date.now();
   const result = spawnSync(npmCmd, ["rebuild", "better-sqlite3"], {