docs(readme): fix stale "scaffold" status — indexer is in production

[satyakwok]

11 of N in the all-READMEs polish sweep. Status line claimed "scaffold — Phase 1 in progress" from initial draft. Indexer actually powers production REST + scan UI on both mainnet + testnet. Updated to reflect production state + the Rust rewrite trajectory at Sentriscloud/indexer-rs.

Summary by CodeRabbit

• Documentation
  • Updated project status to announce production deployment of the indexer
  • Indexer now supports both mainnet and testnet networks

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

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Review profile: ASSERTIVE

Plan: Pro Plus

Run ID: 379e81e8-d5f8-4b6a-9241-ef00bcdf8b18

📥 Commits

Reviewing files that changed from the base of the PR and between 26cdc15 and 47a2e7a.

📒 Files selected for processing (1)

• README.md

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📝 Walkthrough

Walkthrough

This pull request updates the README "Status" section to announce the indexer's production deployment. The change specifies supported blockchain networks (mainnet chain 7119 and testnet chain 7120) and documents that a parallel Rust rewrite is underway in a separate repository while the TypeScript implementation continues serving production traffic until feature parity is achieved.

Estimated code review effort

🎯 1 (Trivial) | ⏱️ ~2 minutes

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Description check	⚠️ Warning	The description lacks required template sections (Summary structured properly, but missing Test plan and Related sections entirely).	Add the missing Test plan (with verification checklist) and Related (with links to related issues/PRs) sections as specified in the repository template.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title accurately describes the main change: updating a stale README status from 'scaffold' to reflect the production state of the indexer.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch chore/polish-readme-truth

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