-- §7 multi-repo ownership: the `projects` registry + wiring the inert
-- `owner_project` seam.
--
-- A "project" is a repo-root that declaratively MANAGES a slice of the shared
-- group tree (contains its manifest as something it applies, not merely
-- references). §7's model is SINGLE-OWNER-PER-NODE: each group node is owned by
-- exactly one project; the first `pic apply` that declares a `[project]` claims
-- the node, and a second repo applying to an owned node is refused unless it
-- passes a group-admin-gated `--takeover`. Ownership ⟂ RBAC — it records which
-- manifest is authoritative, not whether a principal may act.
--
-- Identity is a committed `[project] slug` (stable across clones); the server
-- assigns the UUID (server-internal). The `owner_project UUID` column already
-- exists on `groups` (0047, inert) — this migration creates the table it was
-- always meant to reference and wires the FK. Apps carry NO owner column: an
-- app inherits ownership from its NEAREST claimed ancestor group (the ancestor
-- walk is the isolation boundary), faithful to §7's "don't co-own a node —
-- split config downward" corollary.

CREATE TABLE projects (
    id         UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    -- Instance-global identity, declared in the repo's committed root manifest
    -- and frozen. First apply with a new slug registers the project.
    slug       TEXT NOT NULL UNIQUE,
    name       TEXT NOT NULL,
    -- The admin who first registered it. SET NULL (not CASCADE) — losing the
    -- creator's account must not orphan-delete the project or un-claim its tree.
    created_by UUID REFERENCES admin_users(id) ON DELETE SET NULL,
    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
);

-- Wire the inert 0047 seam. ON DELETE SET NULL un-claims the owned nodes (they
-- fall back to UI/API-owned) rather than cascading a destructive tree delete —
-- deleting a project must never destroy the groups/apps it happened to manage.
ALTER TABLE groups
    ADD CONSTRAINT groups_owner_project_fk
    FOREIGN KEY (owner_project) REFERENCES projects(id) ON DELETE SET NULL;

-- Ownership lookups: "what does project X own?" (pic projects ls) and the
-- LEFT JOIN behind pic groups ls' owner column.
CREATE INDEX groups_owner_project_idx ON groups (owner_project);