Add GitHub issue pipelines and prompts using gh CLI

gh-issue-impl, gh-issue-research, gh-issue-rewrite, gh-issue-update
pipelines with corresponding prompts for fetch-assess, plan,
implement, and create-pr steps.

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

.wave/prompts/speckit-flow/tasks.md

@@ -0,0 +1,52 @@
+You are generating an actionable, dependency-ordered task breakdown for implementation.
+
+Feature context: {{ input }}
+
+## Working Directory
+
+You are running in an **isolated git worktree** shared with previous pipeline steps.
+Your working directory IS the project root. The feature branch was created by a
+previous step and is already checked out.
+
+## Instructions
+
+Follow the `/speckit.tasks` workflow:
+
+1. Find the feature directory and spec file path from the spec info artifact
+2. Run `.specify/scripts/bash/check-prerequisites.sh --json` to get FEATURE_DIR
+   and AVAILABLE_DOCS
+3. Load from FEATURE_DIR:
+   - **Required**: plan.md (tech stack, structure), spec.md (user stories, priorities)
+   - **Optional**: data-model.md, contracts/, research.md, quickstart.md
+4. Execute task generation:
+   - Extract user stories with priorities (P1, P2, P3) from spec.md
+   - Map entities and endpoints to user stories
+   - Generate tasks organized by user story
+
+5. Write `tasks.md` following the strict checklist format:
+   ```
+   - [ ] [TaskID] [P?] [Story?] Description with file path
+   ```
+
+6. Organize into phases:
+   - Phase 1: Setup (project initialization)
+   - Phase 2: Foundational (blocking prerequisites)
+   - Phase 3+: One phase per user story (priority order)
+   - Final: Polish & cross-cutting concerns
+
+## CONSTRAINTS
+
+- Do NOT spawn Task subagents — work directly in the main context
+- Do NOT use WebSearch — all information is in the spec artifacts
+- Keep the scope tight: generate tasks from existing artifacts only
+
+## Quality Requirements
+
+- Every task must have a unique ID (T001, T002...), description, and file path
+- Mark parallelizable tasks with [P]
+- Each user story phase must be independently testable
+- Tasks must be specific enough for an LLM to complete without additional context
+
+## Output
+
+Produce a JSON status report matching the injected output schema.