Add TurtleTerm macOS packaging plan

Author: mdheller

docs/sourceos/MACOS_PACKAGING.md

@@ -0,0 +1,74 @@
+# TurtleTerm macOS Packaging
+
+## Purpose
+
+TurtleTerm should present as TurtleTerm on macOS, not as a runtime clone.
+
+This document defines the staged macOS application identity and the remaining production hardening work.
+
+## Current staged app identity
+
+The staged app bundle is generated by:
+
+```bash
+packaging/scripts/stage-macos-app.sh <version> <output-dir>
+```
+
+It creates:
+
+```text
+TurtleTerm.app/
+  Contents/
+    Info.plist
+    MacOS/turtleterm
+    Resources/turtleterm-icon.svg
+    libexec/turtle-term/
+    etc/turtle-term/turtleterm.lua
+    share/turtle-term/
+```
+
+The bundle metadata uses:
+
+```text
+CFBundleName=TurtleTerm
+CFBundleDisplayName=TurtleTerm
+CFBundleIdentifier=ai.sourceos.TurtleTerm
+CFBundleExecutable=turtleterm
+```
+
+## Runtime boundary
+
+The app launches TurtleTerm through `Contents/MacOS/turtleterm` and keeps private terminal runtime files under:
+
+```text
+Contents/libexec/turtle-term/
+```
+
+The public product executable remains:
+
+```text
+turtleterm
+```
+
+## Production hardening still required
+
+The staged app is not yet a complete production macOS distribution. Remaining work:
+
+1. Generate a proper `.icns` icon from TurtleTerm brand assets.
+2. Replace or patch runtime app/window metadata where deeper internals expose non-product names.
+3. Add codesigning.
+4. Add notarization.
+5. Add DMG or PKG packaging lane.
+6. Add Gatekeeper validation workflow.
+7. Add update/rollback story.
+
+## Acceptance criteria
+
+macOS packaging is product-ready when:
+
+1. `TurtleTerm.app` opens as TurtleTerm.
+2. Activity Monitor, Dock, Finder, and app metadata show TurtleTerm.
+3. App icon is TurtleTerm-branded.
+4. App is signed and notarized.
+5. Release artifacts include checksums, manifest, SBOM, and attestations.
+6. Required third-party notices are included without taking over the product surface.