Fix: validate account_id as StrKey G-address

[TheShnider]

Description

Closes #1117

Type of Change

• 🐛 Bug fix (non-breaking change which fixes an issue)
• ✨ New feature (non-breaking change which adds functionality)
• 💥 Breaking change (fix or feature that would cause existing functionality to not work as expected)
• 📝 Documentation update
• 🔧 Configuration change
• ♻️ Code refactoring
• ⚡ Performance improvement
• ✅ Test addition/improvement

Security Impact

• This change involves cryptographic operations
• This change affects account validation logic
• This change modifies smart contracts
• This change handles user private keys
• This change affects authorization/authentication
• No security impact

Testing

• Unit tests added/updated
• Integration tests added/updated
• Manual testing performed
• E2E tests added/updated (if applicable)

Test Coverage

• Current coverage: __%
• New/modified code coverage: __%

Manual Testing Steps

Breaking Changes

• This PR introduces breaking changes

Checklist

• My code follows the project's style guidelines
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings or errors
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published
• Any flaky-test quarantine entry includes a linked follow-up issue, owner, expiry, and stable failure signature

For High-Security Changes

• I have documented all security assumptions
• I have considered attack vectors
• I have added security-focused test cases
• I have reviewed against the threat model

Related Issues

Closes #
Related to #

Additional Context

Reviewer Notes

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Summary by CodeRabbit

• Bug Fixes

  • Improved account ID validation to accept only valid Stellar Ed25519 public keys.
  • Invalid or malformed account identifiers are now rejected more reliably.

• Tests

  • Updated account activity API tests to use valid Stellar public keys.

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📝 Walkthrough

Walkthrough

Changes

Account ID validation

Layer / File(s)	Summary
Stellar account ID validation services/indexer/Cargo.toml, services/indexer/src/api/account_activity.rs	The indexer adds stellar-strkey and validates account IDs by parsing Stellar StrKeys. Only Ed25519 public keys are accepted.
Account activity test inputs services/indexer/tests/account_activity_api_test.rs	Integration tests use a valid Stellar public key for account activity listing, pagination, filtering, lookup, and validation cases.

Estimated code review effort: 2 (Simple) | ~10 minutes

Suggested reviewers: wheval

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Linked Issues check	⚠️ Warning	The PR adds StrKey parsing, but tests only replace IDs and do not cover invalid inputs or confirm stable 400 behavior before database access.	Add tests for malformed account_id values and verify the handler returns the stable 400 response before querying the database.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly describes the main change: validating account_id as a Stellar StrKey G-address.
Out of Scope Changes check	✅ Passed	All dependency, validation, and test changes directly support issue #1117.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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Warning

⚠️ This pull request shows signs of AI-generated slop (redundant_comments). It has been flagged by CodeRabbit slop detection and should be reviewed carefully.

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Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@services/indexer/src/api/account_activity.rs`:
- Around line 64-69: Update the invalid-account test in the account activity API
tests to use a 56-character G-prefixed account value with an invalid checksum
instead of "invalid", ensuring it reaches the
stellar_strkey::Strkey::from_string validation path. Assert that the response
error field equals "invalid_filter", while preserving the existing
invalid-account request flow.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

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• Create a new PR with the fixes

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ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro Plus

Run ID: 3dbd7419-5276-4e76-a9cd-c917a0b3b004

📥 Commits

Reviewing files that changed from the base of the PR and between 4f8d69c and 4ac76c6.

📒 Files selected for processing (3)

• services/indexer/Cargo.toml
• services/indexer/src/api/account_activity.rs
• services/indexer/tests/account_activity_api_test.rs