feat(invites): team invite links — admin create/revoke, public accept (#42)

* feat(branding): white-label — public /branding, admin write, shell theming

app_settings branding.* keys (product name, logo/favicon URLs, accent
color, docs/support links). Public GET /branding so login and shell
theme pre-auth; admin writes via PUT /settings.

useBranding() applies document.title, accent CSS var and favicon;
BrandWordmark replaces hardcoded wordmarks; admin Platform settings
gain a Branding form. MCP containr_branding_get + settings_update.

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

* feat(invites): team invite links — admin create/revoke, public accept

Admins mint single-use invite links (sha256-hashed token at rest,
optional email binding, configurable TTL). Public endpoints let the
accept page validate the link and register — working even while
public signup is disabled.

- migration + sqlc queries/model for user_invites
- POST /admin/invites (returns one-time token+url), GET list, DELETE revoke
- GET /auth/invites/:token public validation, POST /auth/accept-invite
- CLI containr invites list|create|revoke; MCP invites tools
- /auth/accept-invite page (expired/used/invalid states, bound-email lock)
- Admin page Team invites section: create, copy link, revoke
- OpenAPI + generated types + CLI guide

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

---------

Co-authored-by: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

ROADMAP2.md

@@ -304,8 +304,12 @@ and wired refs, one click or one CLI call.
 - [ ] **Interactive terminal** — upgrade exec to WS PTY (`xterm.js`);
   `nodes/:id/terminal` via agent (dflow's wetty without the extra
   container).
-- [ ] **Team invites** — `POST /invites` → signed link → join flow;
-  replaces manual-only user creation.
+- [x] **Team invites** — `POST /admin/invites` returns a one-time
+  link (sha256-hashed token at rest, optional email binding, TTL);
+  public `GET /auth/invites/:token` validates and
+  `POST /auth/accept-invite` registers — works while public signup is
+  closed. `/auth/accept-invite` page, admin manage/revoke UI,
+  `containr invites` CLI + MCP tools.
 - [ ] **Impersonate user** — admin support tool, audit-logged.
 - [ ] **GitHub App manifest flow** — `POST /git/github-app/manifest`
   returns manifest + redirect; instance self-provisions its App