Add prompt recipe manifests and command palette

[WalksWithASwagger]

Context

Repeated workflows are currently scattered across controls. The product needs reusable recipes such as article with receipts, client brief, issue wave, social pack, and SongForge prompt pack.

Source: docs/WHISPERFORGE-MASTER-PLAN-2026-05-18.md (wf-recipe-system, Phase 3).

Linear: BC-224.

Acceptance Criteria

• Define a minimal recipe manifest format for inputs, stages, provider/model defaults, KB mode, output sections, eval checks, and handoff targets.
• Load profile-level and default recipes without breaking current manual controls.
• Add a command palette or compact selector for running a recipe from a capture/current input.
• Persist the recipe id and effective settings in run artifacts.
• Include at least three built-in recipes covering article, brief/social, and issue/handoff workflows.

Tests/Evals

• Unit tests for recipe loading, precedence, and effective-settings resolution.
• UI smoke if the palette is visible in Streamlit.

Verification

• make test
• venv/bin/python tests/ui_smoke.py
• git diff --check

Agent Instructions

Keep the manifest small and explicit. Prefer YAML/JSON parsed through a structured loader, and reuse existing profile override conventions.

Out of Scope

Do not remove existing manual generation controls in this issue.

[WalksWithASwagger]

PR #27 is ready for review: https://github.com/WalksWithASwagger/spektorAI/pull/27\n\nThis slice adds structured recipe manifests, three built-in recipes, a compact command palette selector, recipe default application, and run-artifact/source-receipt recipe metadata. Verified with py_compile, targeted tests, full test suite, UI smoke, local Playwright palette check, make smoke, git diff --check, and roadmap JSON validation.