-- Slice 3.5d — agent → team-template lineage.
--
-- When a team is minted from a template we record which template +
-- version + role_slot produced each agent. Level-up (Slice 8.5) reads
-- this to:
--   - diff the agent's brain against the seeded brain_seed
--   - route "add skill to my team's template" proposals to the right
--     template row + version
--   - offer template-upgrade prompts when the template ships a new
--     version and the agent is still on an older one
--
-- Also: adds a `first_seeded_at` timestamp on agents so the brain-seed
-- ingestion is idempotent — we skip re-seeding an agent whose brain
-- was already populated from a template.

CREATE TABLE agent_template_link (
    agent_id         UUID PRIMARY KEY REFERENCES agents(id) ON DELETE CASCADE,
    template_id      UUID NOT NULL REFERENCES team_templates(id) ON DELETE CASCADE,
    template_version INT  NOT NULL,
    role_slot        TEXT NOT NULL,
    -- When we ingested brain_seed. NULL means the link was recorded
    -- but seeding hasn't run yet (rare — recovery / retry path).
    seeded_at        TIMESTAMPTZ,
    created_at       TIMESTAMPTZ NOT NULL DEFAULT now(),
    -- Ensures we can query "all agents on template X, version Y"
    -- without a table scan when the level-up proposer runs.
    FOREIGN KEY (template_id, role_slot)
        REFERENCES template_roles(template_id, slot)
);
CREATE INDEX agent_template_link_template_idx
    ON agent_template_link (template_id, template_version);
CREATE INDEX agent_template_link_role_idx
    ON agent_template_link (template_id, role_slot);