feat(agent): add strict reviewer and Pi runtime

[Caltsic]

What changed

• adds the strict circuit reviewer and provider configuration controls
• adds the Pi 0.84.1 runtime behind a legacy | pi feature flag
• supports OpenAI-compatible/DeepSeek and Anthropic through the EASYAnalyse-owned runtime protocol
• makes provider response extraction fail-open so raw/partial text is retained
• shares the semantic-v4 terminal, connectivity, layout, and network-line contract across runtimes
• makes ordinary replies plain text and Blueprint creation tool-only through create_blueprint_candidate
• preserves provider text and suppresses duplicate Blueprint insertion

Why

The previous runtime could discard otherwise useful model output when structured parsing or later tool-loop validation failed. The Pi proof of concept provides a maintained agent base while keeping the UI and persisted protocol independent from Pi-specific types.

Validation

• npm run verify
• cargo test --manifest-path easyanalyse-desktop/src-tauri/crates/easyanalyse-core/Cargo.toml
• GitHub Actions desktop and Rust jobs