Restructure release infra for multiple platforms; migrate real win keys

PyInstaller doesn't cross-compile and TUF metadata filenames aren't
platform-prefixed, so a shared updates/ release and repo tree can't
safely hold more than one OS's build — a second platform's publish
would silently overwrite the first's trust root and metadata.

- scripts/release/repo_init.py, repo_release.py: auto-detect platform
  (win/mac/linux) and operate inside scripts/release/<platform>/ instead
  of a flat scripts/release/ tree.
- labui.spec: bundles root.json from this platform's own tree.
- core/updater.py: points at releases/download/updates-<platform>/
  instead of a single shared updates/ tag.
- Moved the existing real keystore/repository/config (already used for
  a live Windows release) from the old flat path into
  scripts/release/win/ — same keys, same signed metadata, just
  relocated. No new keys generated, existing installs still trust it.
- .gitignore updated for the per-platform paths, plus temporary rules
  covering the old flat path during migration.
- docs/building.md, scripts/release/README.md: rewritten for the
  per-platform flow, including a note that Linux builds should happen
  on Linux/WSL2 (no cross-compiling) and that a bare .exe doesn't
  belong on the updates-<platform> release — only the TUF metadata +
  signed target archive do.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

1 files changed, 0 insertions, 34 deletions

diff --git a/scripts/release/.tufup-repo-config b/scripts/release/.tufup-repo-config
deleted file mode 100644
index e072c2a..0000000
--- a/scripts/release/.tufup-repo-config
+++ /dev/null
@@ -1,34 +0,0 @@
-{
-    "app_name": "labui",
-    "app_version_attr": null,
-    "binary_diff": null,
-    "encrypted_keys": [],
-    "expiration_days": {
-        "root": 365,
-        "snapshot": 90,
-        "targets": 90,
-        "timestamp": 90
-    },
-    "key_map": {
-        "root": [
-            "root"
-        ],
-        "snapshot": [
-            "snapshot"
-        ],
-        "targets": [
-            "targets"
-        ],
-        "timestamp": [
-            "timestamp"
-        ]
-    },
-    "keys_dir": "keystore",
-    "repo_dir": "repository",
-    "thresholds": {
-        "root": 1,
-        "snapshot": 1,
-        "targets": 1,
-        "timestamp": 1
-    }
-}
\ No newline at end of file