[High] Solver Reputation Score v2 with Time Decay and Transparency

[james2177]

Description:
Design and implement a reputation score combining fill rate, fill latency, slashes, quote-honouring, and volume with exponential time decay, exposed with a full breakdown via API.

Problem Statement & Context:
The leaderboard ranks by simple counters. It rewards historical volume over current reliability and offers no insight into why a solver ranks where it does, which matters for routing and for community trust.

Scope & Acceptance Criteria:

• Documented formula (RFC in docs/rfcs/) with configurable weights and half-life.
• Computed from solver_fills and slash records; recalculated incrementally.
• GET /solvers/:addr/reputation returns score, components, and history (daily snapshots).
• Leaderboard supports sort=reputation; quote tie-breaking uses it.
• Out of scope: on-chain reputation.

Implementation Guidelines:

1. Key Files/Modules: new src/solvers/reputation.service.ts, src/solvers/leaderboard-query.ts, docs/rfcs/.
2. Design/Architecture: Pure scoring function + persistence of snapshots; deterministic and reproducible from raw data.
3. Edge Cases/Constraints: New solvers (cold start) must not be unfairly ranked last — Bayesian prior.
4. Testing: Deterministic fixture tests; property tests (more slashes never raise score).

Definition of "Done": Common DoD; RFC merged.

Resources:

• Design reference: N/A (backend-only)
• docs/rfcs/0000-template.md
• https://www.evanmiller.org/how-not-to-sort-by-average-rating.html

---

Common Definition of "Done" (applies in addition to the criteria above):

• Code written, tested, and documented (TSDoc on public APIs, README/runbook/ADR updates where behaviour changes).
• All acceptance criteria met; npm run lint, npm run typecheck, npm test, npm run test:e2e pass in CI.
• PR follows .github/PULL_REQUEST_TEMPLATE, uses a Conventional Commit title (enforced by commitlint), includes test output / metrics screenshots, and references the issue.
• New env vars are added to .env.example variants and src/config/env.validation.ts (the check:env-drift script must pass).
• Reviewed and approved by at least one CODEOWNER.

[james2177]

Related prior work: Builds on #115: reputationScore is already computed in the leaderboard (src/solvers/solvers.controller.ts). v2 replaces that formula with decay, components, and snapshots.

[Shaqoo]

@Shaqoo has applied to work on this issue as part of the Stellar Wave Program's 9th wave.

@maintainer I’d like to work on this issue. I’ll implement the reputation scoring with time decay, transparent breakdowns, and deterministic tests while keeping the scoring logic reproducible and easy to validate.

ℹ️ Repo Maintainers: To accept this application, review their application or assign @Shaqoo to this issue.

[scarface-dev1]

@scarface-dev1 has applied to work on this issue as part of the Stellar Wave Program's 9th wave.

please i will love to work on these issue

ℹ️ Repo Maintainers: To accept this application, review their application or assign @scarface-dev1 to this issue.

[dynamicwearsng-debug]

@dynamicwearsng-debug has applied to work on this issue as part of the Stellar Wave Program's 9th wave.

i will like to work on thiss issues

ℹ️ Repo Maintainers: To accept this application, review their application or assign @dynamicwearsng-debug to this issue.

[benedictworks-home]

@benedictworks-home has applied to work on this issue as part of the Stellar Wave Program's 9th wave.

Hi maintainer, please assign

ℹ️ Repo Maintainers: To accept this application, review their application or assign @benedictworks-home to this issue.

[drips-wave]

Congratulations, @benedictworks-home! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on September 30, 2026.

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