feat: Implement phases 6 to 9 of the review cycle fix process, including discovery, batching, parallel planning, execution, and completion

- Added Phase 6: Fix Discovery & Batching with intelligent grouping and batching of findings.
- Added Phase 7: Fix Parallel Planning to launch planning agents for concurrent analysis and aggregation of partial plans.
- Added Phase 8: Fix Execution for stage-based execution of fixes with conservative test verification.
- Added Phase 9: Fix Completion to aggregate results, generate summary reports, and handle session completion.
- Introduced new frontend components: ResizeHandle for draggable resizing of sidebar panels and useResizablePanel hook for managing panel sizes with localStorage persistence.
- Added PowerShell script for checking TypeScript errors in source code, excluding test files.

.codex/skills/review-cycle/phases/03-aggregation.md

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+# Phase 3: Aggregation
+
+> Source: Shared from `commands/workflow/review-session-cycle.md` + `commands/workflow/review-module-cycle.md` Phase 3
+
+## Overview
+
+Load all dimension results, calculate severity distribution, identify cross-cutting concerns, and decide whether to enter iterative deep-dive (Phase 4) or proceed to completion (Phase 5).
+
+## Execution Steps
+
+### Step 3.1: Load Dimension Results
+
+- Load all dimension JSON files from `{outputDir}/dimensions/`
+- Parse each file following review-dimension-results-schema.json
+- Handle missing files gracefully (log warning, skip)
+
+### Step 3.2: Calculate Severity Distribution
+
+- Count findings by severity level: critical, high, medium, low
+- Store in review-state.json `severity_distribution` field
+
+### Step 3.3: Cross-Cutting Concern Detection
+
+**Cross-Cutting Concern Detection**:
+1. Files appearing in 3+ dimensions = **Critical Files**
+2. Same issue pattern across dimensions = **Systemic Issue**
+3. Severity clustering in specific files = **Hotspots**
+
+### Step 3.4: Deep-Dive Selection
+
+**Deep-Dive Selection Criteria**:
+- All critical severity findings (priority 1)
+- Top 3 high-severity findings in critical files (priority 2)
+- Max 5 findings per iteration (prevent overwhelm)
+
+### Step 3.5: Decision Logic
+
+**Iteration Trigger**:
+- Critical findings > 0 OR
+- High findings > 5 OR
+- Critical files count > 0
+
+If any trigger condition is met, proceed to Phase 4 (Iterative Deep-Dive). Otherwise, skip to Phase 5 (Completion).
+
+### Step 3.6: Update State
+
+- Update review-state.json with aggregation results
+- Update review-progress.json
+
+**Phase 3 Orchestrator Responsibilities**:
+- Load all dimension JSON files from dimensions/
+- Calculate severity distribution: Count by critical/high/medium/low
+- Identify cross-cutting concerns: Files in 3+ dimensions
+- Select deep-dive findings: Critical + high in critical files (max 5)
+- Decision logic: Iterate if critical > 0 OR high > 5 OR critical files exist
+- Update review-state.json with aggregation results
+
+## Severity Assessment Reference
+
+**Severity Levels**:
+- **Critical**: Security vulnerabilities, data corruption risks, system-wide failures, authentication/authorization bypass
+- **High**: Feature degradation, performance bottlenecks, architecture violations, significant technical debt
+- **Medium**: Code smells, minor performance issues, style inconsistencies, maintainability concerns
+- **Low**: Documentation gaps, minor refactoring opportunities, cosmetic issues
+
+## Output
+
+- Variables: severityDistribution, criticalFiles, deepDiveFindings, shouldIterate (boolean)
+- State: review-state.json updated with aggregation results
+
+## Next Phase
+
+- If shouldIterate: [Phase 4: Iterative Deep-Dive](04-iterative-deep-dive.md)
+- Else: [Phase 5: Review Completion](05-review-completion.md)