chore: update arbitrum event cache to use alchemy

[kaladinlight]

Summary by CodeRabbit

• Chores
  • Updated backend infrastructure configuration for Arbitrum services. The underlying API provider has been changed, but no user-facing functionality has been affected.

[coderabbitai]

📝 Walkthrough

Walkthrough

The Arbitrum API infrastructure is migrated from Infura to Alchemy by updating the transport endpoint in the controller and replacing the API key environment variable from INFURA_API_KEY to ALCHEMY_API_KEY across configuration files.

Changes

Cohort / File(s)	Summary
Arbitrum API Provider Migration node/coinstacks/arbitrum/api/src/controller.ts, node/coinstacks/arbitrum/sample.env	Updated infuraClient transport endpoint from Infura mainnet URL to Alchemy-based URL; replaced INFURA_API_KEY with ALCHEMY_API_KEY in secret environment variables.

Estimated code review effort

🎯 1 (Trivial) | ⏱️ ~5 minutes

Poem

🐰 From Infura's nest to Alchemy's gleam,
Our Arbitrum chains now stream,
With endpoints fresh and keys renewed,
The infrastructure's been transfused,
One hop, one skip, the migration's through! ✨

🚥 Pre-merge checks | ✅ 3

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately describes the main change: switching the Arbitrum API from Infura to Alchemy, which is reflected in both the controller.ts endpoint change and the sample.env variable swap.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

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✨ Finishing Touches

• 📝 Generate docstrings (stacked PR)
• 📝 Generate docstrings (commit on current branch)

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch arbitrum-alchemy

📝 Coding Plan

• Generate coding plan for human review comments

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[coderabbitai]

Caution

Some comments are outside the diff and can’t be posted inline due to platform limitations.

⚠️ Outside diff range comments (1)

node/coinstacks/arbitrum/api/src/controller.ts (1)

15-21: ⚠️ Potential issue | 🔴 Critical

Alchemy migration is incomplete: controller still requires INFURA_API_KEY.

The endpoint was switched to Alchemy, but this file still reads and validates INFURA_API_KEY. With sample.env now using ALCHEMY_API_KEY, the service can fail fast at startup due to missing env var.

Suggested fix

-const INFURA_API_KEY = process.env.INFURA_API_KEY
+const ALCHEMY_API_KEY = process.env.ALCHEMY_API_KEY
 ...
-if (!INFURA_API_KEY) throw new Error('INFURA_API_KEY env var not set')
+if (!ALCHEMY_API_KEY) throw new Error('ALCHEMY_API_KEY env var not set')
 ...
 const infuraClient = createPublicClient({
   chain: arbitrum,
-  transport: http(`https://arb-mainnet.g.alchemy.com/v2/${INFURA_API_KEY}`),
+  transport: http(`https://arb-mainnet.g.alchemy.com/v2/${ALCHEMY_API_KEY}`),
 })

Also applies to: 34-34

🤖 Prompt for AI Agents

Verify each finding against the current code and only fix it if needed.

In `@node/coinstacks/arbitrum/api/src/controller.ts` around lines 15 - 21, The
controller still reads and validates INFURA_API_KEY but the project migrated to
Alchemy; add reading of ALCHEMY_API_KEY (const ALCHEMY_API_KEY =
process.env.ALCHEMY_API_KEY) and replace/remove uses and checks of
INFURA_API_KEY so startup validates ALCHEMY_API_KEY instead (update any throw
new Error('INFURA_API_KEY env var not set') to reference ALCHEMY_API_KEY and
remove the unused INFURA_API_KEY constant), locating changes around the
INFURA_API_KEY, RPC_URL and RPC_API_KEY declarations in controller.ts.

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Outside diff comments:
In `@node/coinstacks/arbitrum/api/src/controller.ts`:
- Around line 15-21: The controller still reads and validates INFURA_API_KEY but
the project migrated to Alchemy; add reading of ALCHEMY_API_KEY (const
ALCHEMY_API_KEY = process.env.ALCHEMY_API_KEY) and replace/remove uses and
checks of INFURA_API_KEY so startup validates ALCHEMY_API_KEY instead (update
any throw new Error('INFURA_API_KEY env var not set') to reference
ALCHEMY_API_KEY and remove the unused INFURA_API_KEY constant), locating changes
around the INFURA_API_KEY, RPC_URL and RPC_API_KEY declarations in
controller.ts.

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: 1996a81f-c360-4fe9-81d4-0a7b9c58ac4e

📥 Commits

Reviewing files that changed from the base of the PR and between b0e61a1 and 4c7d47e.

📒 Files selected for processing (2)

• node/coinstacks/arbitrum/api/src/controller.ts
• node/coinstacks/arbitrum/sample.env