docs: simplify ESM init file in SDK instrumentation prompt

[sohankshirsagar]

Summary

Updates the agent's SDK instrumentation prompt to reflect that @use-tusk/drift-node-sdk now auto-registers ESM loader hooks inside TuskDrift.initialize(). Users no longer need to manually call register() / pathToFileURL() in their init file — the ESM init file is now identical to the CJS one.

Corresponding Node SDK change: Use-Tusk/drift-node-sdk#146

Changes

• Removed the separate ESM init file code block from phase_instrument_sdk.md that included manual register("@use-tusk/drift-node-sdk/hook.mjs", ...) and pathToFileURL imports
• Consolidated CJS and ESM init file examples into a single block, since they are now identical
• Added a note that the SDK automatically registers ESM loader hooks when needed
• Entry point setup (Step 3) is unchanged — --import is still required for ESM, and CJS still uses first-import

[cubic-dev-ai]

No issues found across 1 file