feat(FN-3783): add review panel plugin for fusion reports with type definit

The merge delivers the **Reports Review Panel** (FN-3783) as a multi-step plugin feature — defining review panel types, implementing orchestration logic, and wiring them through the fusion-plugin-reports entry point — alongside a collection of complementary improvements: section-aware prompt compact

Fusion-Task-Id: FN-3783

plugins/fusion-plugin-reports/README.md

@@ -2,4 +2,88 @@
 
 Generates HTML system activity reports with multi-agent review.
 
-> Scaffold-only package delivered in FN-3778. Runtime scheduling, report generation, review orchestration, publishing, and dashboard view behavior are implemented in follow-up tasks FN-3779 through FN-3787.
+## Review Panel
+
+The plugin exposes `runReviewPanel()` / `runGeneratedReportReview()` to fan out a generated report draft to multiple reviewer agents in parallel.
+
+### Panel member settings shape
+
+Each reviewer uses this contract:
+
+```ts
+{
+  id: string;
+  name: string;
+  perspective: string;
+  promptTemplateId?: string;
+  provider?: string;
+  modelId?: string;
+}
+```
+
+- `perspective` is appended to the reviewer system prompt.
+- `promptTemplateId` selects a template from `settings.reviewPromptTemplates[templateId]` when present.
+- `provider` + `modelId` optionally override model selection per reviewer.
+
+### Prompt template contract
+
+`runReviewPanel` resolves reviewer templates in this order:
+
+1. `settings.reviewPromptTemplates[promptTemplateId ?? id]`
+2. `settings.reviewPrompt`
+3. Built-in fallback (`DEFAULT_REVIEW_PROMPT`)
+
+This is the temporary compatibility contract until FN-3782 lands shared review-template helpers.
+
+### Individual review shape
+
+```ts
+{
+  memberId: string;
+  memberName: string;
+  perspective: string;
+  verdict: "approve" | "revise" | "reject";
+  summary: string;
+  highlights: string[];
+  lowlights: string[];
+  suggestions: string[];
+  rawText: string;
+  durationMs: number;
+}
+```
+
+### Combined review shape
+
+```ts
+{
+  overallVerdict: "approve" | "revise" | "reject";
+  consensusSummary: string;
+  mergedHighlights: string[];
+  mergedLowlights: string[];
+  mergedSuggestions: string[];
+  individual: IndividualReview[];
+  failures: ReviewFailure[];
+}
+```
+
+Aggregation is deterministic:
+
+- verdict precedence: `approve < revise < reject`
+- merged arrays are case-insensitive de-duped, first-seen order, max 25 items each
+- consensus summary is generated locally from reviewer summaries (no second AI call)
+
+### Timeout and failure semantics
+
+- Each reviewer has a hard timeout (`120_000ms`).
+- A single reviewer failure never aborts the full panel.
+- Failures are returned as:
+
+```ts
+{
+  memberId: string;
+  reason: "timeout" | "parse_error" | "session_unavailable" | "exception";
+  message: string;
+}
+```
+
+- If all reviewers fail, combined verdict is `reject` with an explicit consensus summary describing panel failure.