feat: add pi-agent tool type migration

- Adds pi-agent to tool_types table with terminal interface
- Includes Dockerfile template for pi.dev coding agent
- Idempotent: checks for existing entry before insert

apps/api/alembic/versions/20260527160017_add_pi_agent_tool_type.py

@@ -0,0 +1,118 @@
+"""add pi agent tool type
+
+Revision ID: 20260527_160017_add_pi_agent
+Revises: f3d2dc90ba3a
+Create Date: 2026-05-27T16:00:17
+
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+import uuid
+
+# revision identifiers, used by Alembic.
+revision: str = "20260527_160017_add_pi_agent"
+down_revision: Union[str, None] = "f3d2dc90ba3a"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+PI_AGENT_ID = uuid.UUID("d07b8376-2151-4119-8c1d-27f792aae9a3")
+
+
+def upgrade() -> None:
+    # Check if pi-agent already exists
+    conn = op.get_bind()
+    result = conn.execute(
+        sa.text("SELECT id FROM tool_types WHERE name = 'pi-agent'")
+    ).fetchone()
+    
+    if result is None:
+        conn.execute(
+            sa.text("""
+                INSERT INTO tool_types (
+                    id, name, display_name, description, category,
+                    interface_type, requires_port, default_port,
+                    definition_type, dockerfile_template, required_variables,
+                    created_at, updated_at
+                ) VALUES (
+                    :id, :name, :display_name, :description, :category,
+                    :interface_type, :requires_port, :default_port,
+                    :definition_type, :dockerfile_template, :required_variables,
+                    now(), now()
+                )
+            """),
+            {
+                "id": PI_AGENT_ID,
+                "name": "pi-agent",
+                "display_name": "Pi Agent",
+                "description": "Pi coding agent terminal environment with nvim, ranger, and tmux",
+                "category": "development",
+                "interface_type": "terminal",
+                "requires_port": False,
+                "default_port": 0,
+                "definition_type": "dockerfile",
+                "dockerfile_template": """# Pi Coding Agent - Terminal-based coding harness
+FROM ubuntu:24.04
+
+ENV DEBIAN_FRONTEND=noninteractive
+
+# Install base dependencies
+RUN apt-get update && apt-get install -y \\
+    curl \\
+    wget \\
+    git \\
+    neovim \\
+    ranger \\
+    tmux \\
+    htop \\
+    tree \\
+    jq \\
+    ca-certificates \\
+    python3 \\
+    python3-pip \\
+    build-essential \\
+    && rm -rf /var/lib/apt/lists/*
+
+# Install Node.js (required for Pi)
+RUN curl -fsSL https://deb.nodesource.com/setup_20.x | bash - \\
+    && apt-get install -y nodejs \\
+    && rm -rf /var/lib/apt/lists/*
+
+# Install Pi Coding Agent globally
+RUN npm install -g --ignore-scripts @earendil-works/pi-coding-agent
+
+# Create non-root user
+RUN useradd -m -s /bin/bash user
+WORKDIR /home/user
+
+# Set up git
+RUN git config --global init.defaultBranch main \\
+    && git config --global user.email "dev@headquarter.local" \\
+    && git config --global user.name "Developer"
+
+# Create default tmux config
+RUN echo 'set -g mouse on\\nset -g default-terminal "screen-256color"' > /home/user/.tmux.conf
+
+# Create default ranger config
+RUN mkdir -p /home/user/.config/ranger \\
+    && echo 'set preview_files true\\nset use_preview_script true' > /home/user/.config/ranger/rc.conf
+
+# Set up Pi config directory
+RUN mkdir -p /home/user/.pi/agent
+
+USER user
+
+# Default to bash (Pi is invoked manually via `pi` command)
+CMD ["/bin/bash"]""",
+                "required_variables": ["REPO_PATH"],
+            }
+        )
+
+
+def downgrade() -> None:
+    conn = op.get_bind()
+    conn.execute(
+        sa.text("DELETE FROM tool_types WHERE name = 'pi-agent'")
+    )