feat: add economic rails and scale guardrails

[SayandB]

Closes #16
Task: T-006

Summary

• add a wallet ledger with guarded credit/debit operations
• add policy-driven scale decisions constrained by budget and load

Tracking

Milestone: M5 — Economic and scale layer. Owner: SayandB. AI review and CI checks run on this PR.

Validation and risk

• pytest -q (see current CI matrix)
• budget values are simulated guardrails; no external payment or cloud provisioning is performed.

No independent reviewer is available among repository collaborators; maintainer review is still required.

[github-actions]

AI review summary

• Reviewed for task alignment, design fit, security posture, and test coverage.
• Expected gate: lint, test (3.10), test (3.11), task-linkage must pass before merge.
• Review focus: maintainability, dependency direction, edge-case correctness, and rollback risk.
• PR: feat: add economic rails and scale guardrails

This workflow acts as an AI-assisted review placeholder. Human maintainer confirmation remains required before merge.

[github-actions]

AI review summary

• Reviewed for task alignment, design fit, security posture, and test coverage.
• Expected gate: lint, test (3.10), test (3.11), task-linkage must pass before merge.
• Review focus: maintainability, dependency direction, edge-case correctness, and rollback risk.
• PR: feat: add economic rails and scale guardrails

This workflow acts as an AI-assisted review placeholder. Human maintainer confirmation remains required before merge.

[github-actions]

PR Reviewer Guide 🔍

Here are some key observations to aid the review process:

⏱️ Estimated effort to review: 3 🔵🔵🔵⚪⚪

🧪 PR contains tests

🔒 No security concerns identified

⚡ No major issues detected

[SayandB]

Tracking update: linked to T-006 / issue #16, milestone M5, owner SayandB, and labeled enhancement plus review effort 3/5. AI review and CI checks are attached to this PR. Independent reviewer assignment is pending another repository collaborator.