code-quality

<CRITICAL_DIRECTIVE> Enforce Staff-level procedural rigor, the Senior Ladder, and Enterprise-Grade software architecture. </CRITICAL_DIRECTIVE>

<THE_SENIOR_LADDER> The best code is the code never written. Before writing code, stop at the first rung that holds:

1. Does this need to exist? -> Skip it (YAGNI).
2. Already in codebase? -> Reuse existing helper/hook/type/component.
3. Stdlib does it? -> Use standard library.
4. Native platform feature? -> Native HTML5/CSS/DB constraint over heavy libraries (e.g. <input type="date"> over picker lib).
5. Existing dependency? -> Use installed libraries; never add new dependencies for trivial tasks.
6. Can it be one line? -> One line.
7. Only then: write the minimum code that works. Root-cause fix only: grep all callers and fix at the shared root, never patch leaf symptoms. </THE_SENIOR_LADDER>

<ENTERPRISE_STANDARDS>

1. DRY & Single Source of Truth (SSOT): Absolutely NO duplicate logic. Re-use existing project hooks, utilities, and components. If logic repeats >= 2 times, extract it to a shared module immediately.
2. Project Pattern Harmony: NEVER introduce pattern schizophrenia. Before coding, inspect existing sibling files. Strictly adhere to the project's established conventions for state management, data-fetching, error handling, directory structure, and styling.
3. SOLID & Clean Architecture: Enforce Single Responsibility (SRP) and Dependency Inversion (DIP). Maintain strict isolation between UI presentation, domain business logic, and infrastructure/data access.
4. Senior Defensive Engineering:
   • Prevent race conditions and memory leaks (clean up event listeners, timers, abort stale requests with AbortController).
   • Strict runtime data validation (Zod, Pydantic) on all external inputs, APIs, and route params.
   • Comprehensive error boundaries with structured domain errors (no silent failures or ad-hoc console.log).
5. Cyclomatic Complexity & Algorithmic Supremacy: Keep functions atomic with shallow indentation. Default to O(1) lookups instead of O(N^2) loops. Memoize expensive operations.
6. Zero-Tolerance Anti-Patterns: NO any types in TypeScript. NO broad except Exception: blocks in Python. NO inline CSS styles or ad-hoc duplicate UI primitives.
7. Feature Completeness (Anti-Dummy): 100% complete production implementations. NO placeholders, mock arrays, or // TODO stubs. Handle loading, empty, and error states gracefully.
8. Security & Secrets: All credentials, tokens, and sensitive configs MUST come from environment variables. </ENTERPRISE_STANDARDS>

<PROCEDURAL_WORKFLOW>

1. Pattern Reconnaissance: Search and read existing sibling files to identify established project patterns (state, API, styling, error handling).
2. Ladder Check: Evaluate the 7-rung Senior Ladder before adding new code or dependencies.
3. Reuse Audit: Check for existing shared components, hooks, or utilities before creating new ones to maintain DRY.
4. Context Acquisition: Understand imports, contracts, and type definitions before modifying code.
5. Minimal Delta Enforcement: Implement ONLY the requested feature with maximum architectural elegance.
6. Test Gap Analysis & TDD: Ensure tests exist and cover all edge cases before modifying implementation.
7. Local Verification: Run stack linter, typecheck, and test runner via python3 scripts/verify.py --execute.
8. Diff Review: Verify zero duplicate code, zero pattern deviations, and complete feature coverage. </PROCEDURAL_WORKFLOW>