feat(workspaces): per-account tenancy + AI access keys + Cursor integration

Adds logical multi-tenancy on top of Coolify + Gitea so every Vibn
account gets its own isolated tenant boundary, and exposes that
boundary to AI agents (Cursor, Claude Code, scripts) through
per-workspace bearer tokens.

Schema (additive, idempotent — run /api/admin/migrate once after deploy)
  - vibn_workspaces: slug, name, owner, coolify_project_uuid,
    coolify_team_id (reserved for when Coolify ships POST /teams),
    gitea_org, provision_status
  - vibn_workspace_members: room for multi-user workspaces later
  - vibn_workspace_api_keys: sha256-hashed bearer tokens
  - fs_projects.vibn_workspace_id: nullable FK linking projects
    to their workspace

Provisioning
  - On first sign-in, ensureWorkspaceForUser() inserts the row
    (no network calls — keeps signin fast).
  - On first project create, ensureWorkspaceProvisioned() lazily
    creates a Coolify Project (vibn-ws-{slug}) and a Gitea org
    (vibn-{slug}). Failures are recorded on the row, not thrown,
    and POST /api/workspaces/{slug}/provision retries.

Auth surface
  - lib/auth/workspace-auth.ts: requireWorkspacePrincipal() accepts
    either a NextAuth session or "Authorization: Bearer vibn_sk_...".
    The bearer key is hard-pinned to one workspace — it cannot
    reach any other tenant.
  - mintWorkspaceApiKey / listWorkspaceApiKeys / revokeWorkspaceApiKey

Routes
  - GET    /api/workspaces                         list
  - GET    /api/workspaces/[slug]                  details
  - POST   /api/workspaces/[slug]/provision        retry provisioning
  - GET    /api/workspaces/[slug]/keys             list keys
  - POST   /api/workspaces/[slug]/keys             mint key (token shown once)
  - DELETE /api/workspaces/[slug]/keys/[keyId]     revoke

UI
  - components/workspace/WorkspaceKeysPanel.tsx: identity card,
    keys CRUD with one-time secret reveal, and a "Connect Cursor"
    block with copy/download for:
      .cursor/rules/vibn-workspace.mdc — rule telling the agent
        about the API + workspace IDs + house rules
      ~/.cursor/mcp.json — MCP server registration with key
        embedded (server URL is /api/mcp; HTTP MCP route lands next)
      .env.local — VIBN_API_KEY + smoke-test curl
  - Slotted into existing /[workspace]/settings between Workspace
    and Notifications cards (no other layout changes).

projects/create
  - Resolves the user's workspace (creating + provisioning lazily).
  - Repos go under workspace.gitea_org (falls back to GITEA_ADMIN_USER
    for backwards compat).
  - Coolify services are created inside workspace.coolify_project_uuid
    (renamed {slug}-{appName} to stay unique within the namespace) —
    no more per-Vibn-project Coolify Project sprawl.
  - Stamps vibn_workspace_id on fs_projects.

lib/gitea
  - createOrg, getOrg, addOrgOwner, getUser
  - createRepo now routes /orgs/{owner}/repos when owner != admin

Also includes prior-turn auth hardening that was already in
authOptions.ts (CredentialsProvider for dev-local, isLocalNextAuth
cookie config) bundled in to keep the auth layer in one consistent
state.

.env.example
  - Documents GITEA_API_URL / GITEA_API_TOKEN / GITEA_ADMIN_USER /
    GITEA_WEBHOOK_SECRET and COOLIFY_URL / COOLIFY_API_TOKEN /
    COOLIFY_SERVER_UUID, with the canonical hostnames
    (git.vibnai.com, coolify.vibnai.com).

Post-deploy
  - Run once: curl -X POST https://vibnai.com/api/admin/migrate \\
      -H "x-admin-secret: \$ADMIN_MIGRATE_SECRET"
  - Existing users get a workspace row on next sign-in.
  - Existing fs_projects keep working (legacy gitea owner + their
    own per-project Coolify Projects); new projects use the
    workspace-scoped path.

Not in this commit (follow-ups)
  - Wiring requireWorkspacePrincipal into the rest of /api/projects/*
    so API keys can drive existing routes
  - HTTP MCP server at /api/mcp (the mcp.json snippet already
    points at the right URL — no client re-setup when it lands)
  - Backfill script to assign legacy fs_projects to a workspace

Made-with: Cursor

app/api/admin/migrate/route.ts

@@ -139,6 +139,54 @@ export async function POST(req: NextRequest) {
       expires    TIMESTAMPTZ NOT NULL,
       UNIQUE (identifier, token)
     )`,
+
+    // ── Vibn workspaces (logical tenancy on top of Coolify) ──────────
+    // One workspace per Vibn account. Holds a Coolify Project UUID
+    // (the team boundary inside Coolify) and a Gitea org name.
+    `CREATE TABLE IF NOT EXISTS vibn_workspaces (
+      id                    UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+      slug                  TEXT NOT NULL UNIQUE,
+      name                  TEXT NOT NULL,
+      owner_user_id         TEXT NOT NULL,
+      coolify_project_uuid  TEXT,
+      coolify_team_id       INT,
+      gitea_org             TEXT,
+      provision_status      TEXT NOT NULL DEFAULT 'pending',
+      provision_error       TEXT,
+      created_at            TIMESTAMPTZ NOT NULL DEFAULT now(),
+      updated_at            TIMESTAMPTZ NOT NULL DEFAULT now()
+    )`,
+    `CREATE INDEX IF NOT EXISTS vibn_workspaces_owner_idx ON vibn_workspaces (owner_user_id)`,
+
+    `CREATE TABLE IF NOT EXISTS vibn_workspace_members (
+      id           UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+      workspace_id UUID NOT NULL REFERENCES vibn_workspaces(id) ON DELETE CASCADE,
+      user_id      TEXT NOT NULL,
+      role         TEXT NOT NULL DEFAULT 'member',
+      created_at   TIMESTAMPTZ NOT NULL DEFAULT now(),
+      UNIQUE (workspace_id, user_id)
+    )`,
+    `CREATE INDEX IF NOT EXISTS vibn_workspace_members_user_idx ON vibn_workspace_members (user_id)`,
+
+    `CREATE TABLE IF NOT EXISTS vibn_workspace_api_keys (
+      id           UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+      workspace_id UUID NOT NULL REFERENCES vibn_workspaces(id) ON DELETE CASCADE,
+      name         TEXT NOT NULL,
+      key_prefix   TEXT NOT NULL,
+      key_hash     TEXT NOT NULL UNIQUE,
+      scopes       JSONB NOT NULL DEFAULT '["workspace:*"]'::jsonb,
+      created_by   TEXT NOT NULL,
+      last_used_at TIMESTAMPTZ,
+      revoked_at   TIMESTAMPTZ,
+      created_at   TIMESTAMPTZ NOT NULL DEFAULT now()
+    )`,
+    `CREATE INDEX IF NOT EXISTS vibn_workspace_api_keys_workspace_idx ON vibn_workspace_api_keys (workspace_id)`,
+
+    // Tag projects with the workspace they belong to (nullable until backfill).
+    // The pre-existing fs_projects.workspace TEXT column stays for the legacy slug;
+    // this new UUID FK is the canonical link.
+    `ALTER TABLE fs_projects ADD COLUMN IF NOT EXISTS vibn_workspace_id UUID REFERENCES vibn_workspaces(id) ON DELETE SET NULL`,
+    `CREATE INDEX IF NOT EXISTS fs_projects_vibn_workspace_idx ON fs_projects (vibn_workspace_id)`,
   ];
 
   for (const stmt of statements) {