feat(framework): P0 — MIT license + executable-leak sanitization

First phase of the framework constitution alpha. No behavior change for
configured installs.

- Add MIT LICENSE (root + framework bundle) + "license":"MIT" in manifests
- Drop private jarvis-brain credential fallback at 3 sites; default to
  $HOME/.config/mosaic/credentials.json (aligns with #551)
- prevent-memory-write.sh: soft-degrade OpenBrain nudge via ${OPENBRAIN_URL},
  removing hardcoded brain.woltje.com; still blocks the write

Refs #542, closes #569

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

packages/mosaic/framework/tools/qa/prevent-memory-write.sh

@@ -26,7 +26,11 @@ FILE_PATH="${FILE_PATH/#\~/$HOME}"
 # Block writes to Claude Code auto-memory files
 if [[ "$FILE_PATH" =~ /.claude/projects/.+/memory/.*\.md$ ]]; then
   echo "BLOCKED: Do not write agent learnings to ~/.claude/projects/*/memory/ — this is a runtime-specific silo."
-  echo "Use OpenBrain instead: MCP 'capture' tool or REST POST https://brain.woltje.com/v1/thoughts"
+  if [[ -n "${OPENBRAIN_URL:-}" ]]; then
+    echo "Use OpenBrain instead: MCP 'capture' tool or REST POST ${OPENBRAIN_URL%/}/v1/thoughts"
+  else
+    echo "Use OpenBrain instead: the 'capture' MCP tool (set OPENBRAIN_URL for the REST endpoint)."
+  fi
   echo "File blocked: $FILE_PATH"
   exit 2
 fi