chore: initial bootstrap — 5 reusable workflows + scaffolding

Public-readable Tier-1 exception (alongside sporel-meta) for the
practical reason that community pipelines need to call into these
workflows without per-repo deploy-token setup.

5 reusable workflows moved from sporel-meta/.gitea/workflows/ to here
(Plan-B.1: privacy-fix for sporel-meta which stays private with the
proprietary design docs).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

LICENSE

@@ -0,0 +1,27 @@
+Copyright (c) 2026 Calic. All rights reserved.
+
+This software is part of the Sporel platform — **Tier 1 (Official /
+Proprietary)** content per the Three-Tier Licensing Model documented
+in `meta/docs/architecture/licensing-model.md` and ratified by ADR-0027.
+
+This repository is **public-readable** as a deliberate Tier-1
+exception (alongside `sporel-meta`), so that community pipelines can
+call into the reusable CI workflows without per-repo deploy-token
+setup. Public-readability does NOT grant re-licensing rights — the
+content remains all-rights-reserved.
+
+⚠ **WIP — Legal review required before public launch.**  The terms
+below reflect design intent only; the formalized license framework
+will be finalized through legal counsel before the first public
+release. Until then, this notice serves as a placeholder defending
+the platform owner's rights against unintentional re-licensing.
+
+No license is granted to copy, modify, distribute, sublicense, or
+otherwise use this software in any form without prior written
+permission from the copyright holder.
+
+References:
+- Tier 1 (this file): all rights reserved, proprietary
+- Tier 2: bilateral contracts — see `licensing-model.md §4`
+- Tier 3: CC BY-NC-SA 4.0 + asymmetric CLA — applies to
+  community-uploaded libs/modules/assets, not this repo