Implement the 026-roll-initiative feature that adds d20 roll buttons for bestiary combatants' initiative using a click-to-edit pattern (d20 icon when empty, plain text when set), plus a Roll All button in the top bar that batch-rolls for all unrolled bestiary combatants, with randomness confined to the adapter layer and the domain receiving pre-resolved dice values

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

specs/026-roll-initiative/plan.md

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+# Implementation Plan: Roll Initiative
+
+**Branch**: `026-roll-initiative` | **Date**: 2026-03-10 | **Spec**: [spec.md](./spec.md)
+**Input**: Feature specification from `/specs/026-roll-initiative/spec.md`
+
+## Summary
+
+Add a "roll initiative" feature that generates random initiative values (1d20 + modifier) for combatants linked to bestiary creatures. The initiative column uses a click-to-edit pattern: bestiary combatants without a value show a d20 icon (click to roll), combatants with a value show it as plain text (click to edit), and manual combatants show "--" (click to type). A "Roll All" button in the turn navigation bar batch-rolls for all eligible combatants that don't already have initiative. The domain layer receives pre-resolved dice values (never generates randomness itself), and the existing `setInitiative` domain function handles persistence and re-sorting.
+
+## Technical Context
+
+**Language/Version**: TypeScript 5.8 (strict mode, verbatimModuleSyntax)
+**Primary Dependencies**: React 19, Tailwind CSS v4, Lucide React (icons), Vite 6
+**Storage**: N/A (no storage changes — existing localStorage persistence handles initiative via `setInitiativeUseCase`)
+**Testing**: Vitest
+**Target Platform**: Browser (single-user, local-first)
+**Project Type**: Web application (monorepo: domain → application → web adapter)
+**Performance Goals**: Instant — single click produces immediate result
+**Constraints**: Domain layer must remain pure (no randomness, no I/O)
+**Scale/Scope**: Single-user encounter tracker
+
+## Constitution Check
+
+*GATE: Must pass before Phase 0 research. Re-check after Phase 1 design.*
+
+| Principle | Status | Notes |
+|-----------|--------|-------|
+| I. Deterministic Domain Core | PASS | Dice rolls are resolved at the adapter boundary and passed as inputs to domain/application functions. Domain never calls Math.random(). |
+| II. Layered Architecture | PASS | New domain function receives pre-rolled values. Application use case orchestrates. React adapter generates random numbers and wires UI. |
+| III. Agent Boundary | N/A | No agent features involved. |
+| IV. Clarification-First | PASS | Spec is clear; no ambiguities remain. |
+| V. Escalation Gates | PASS | All functionality is within spec scope. |
+| VI. MVP Baseline Language | PASS | No permanent bans introduced. |
+| VII. No Gameplay Rules | PASS | Initiative rolling mechanics are in the spec, not the constitution. |
+
+## Project Structure
+
+### Documentation (this feature)
+
+```text
+specs/026-roll-initiative/
+├── plan.md              # This file
+├── research.md          # Phase 0 output
+├── data-model.md        # Phase 1 output
+├── quickstart.md        # Phase 1 output
+└── tasks.md             # Phase 2 output (via /speckit.tasks)
+```
+
+### Source Code (repository root)
+
+```text
+packages/domain/src/
+├── roll-initiative.ts           # NEW — pure function: (diceRoll, modifier) → initiative value
+├── initiative.ts                # EXISTING — calculateInitiative (reused for modifier)
+├── set-initiative.ts            # EXISTING — reused to apply rolled values
+├── types.ts                     # EXISTING — no changes needed
+├── events.ts                    # EXISTING — no new event types needed (reuses InitiativeSet)
+└── __tests__/
+    └── roll-initiative.test.ts  # NEW — tests for the pure roll function
+
+packages/application/src/
+├── roll-initiative-use-case.ts      # NEW — single combatant roll orchestration
+├── roll-all-initiative-use-case.ts  # NEW — batch roll orchestration
+└── set-initiative-use-case.ts       # EXISTING — called by the new use cases
+
+apps/web/src/
+├── components/
+│   ├── combatant-row.tsx        # MODIFIED — add d20 roll button next to initiative input
+│   ├── turn-navigation.tsx      # MODIFIED — add "Roll All" button
+│   └── d20-icon.tsx             # NEW — inline SVG component (paths copied from root d20.svg)
+└── hooks/
+    └── use-encounter.ts         # EXISTING — no changes needed (roll callbacks live in App.tsx)
+```
+
+**Structure Decision**: Follows the existing monorepo layering. New domain function is minimal (compute initiative from dice roll + modifier). Application use cases orchestrate the domain call and persistence. React components handle randomness generation and UI.
+
+## Complexity Tracking
+
+No constitution violations — table not needed.