Make Boatstack independently developed and verified

[bigboateng]

Why

Boatstack is now developed directly in this repository. Intelligence Flow must no longer synchronize or publish it.

Changes

• removes the upstream sync workflow and sync-specific CI
• preserves the eight runtime check contexts and adds repository-contract
• transfers portable conformance checks for release notes, detached supervision, exports, plans, installers, documentation, claims, assets, and private-data boundaries
• makes Boatstack the editable source in current documentation
• preserves the old import record as immutable IMPORT_PROVENANCE.json
• binds release binaries to the exact Boatstack release commit
• keeps patch releases for runtime changes and skips documentation-only merges

Verification

• go test ./...
• go build ./cmd/boatstack-helper
• go vet ./...
• python3 -m unittest discover -s .github/tests -p "test_*.py" -v (13 tests)
• release-note policy and workflow YAML parsing
• Bash and PowerShell installer parsing
• git diff --check