12-robotics: migrate the 15-task embodied set into the unified pilot format
Adds 14 embodied Harbor tasks alongside the existing pi05-libero, in the same score-preserving format: each directory is a byte-identical copy of the canonical harbor_rp_tasks/ source plus the three diagnostic overlay files (rubric_mapping.json/.yaml, evidence_policy.json).
Verification: tools/validate_package.py was generalised to iterate every task dir (it was hardcoded to pi05-libero) and to report copy=SKIPPED when a source tree is absent rather than pass silently. All 15 tasks report copy=OK + mapping=OK: leaf coverage, per-leaf effective_weight, rubric hashes, the six-capability set and JSON/YAML agreement all check out, and pi05-libero regenerates byte-identical to the already-published copy (its hand-authored capability assignment is pinned, not overwritten).
Excluded from navila/environment: repos/ (habitat-sim v0.1.7 + NaVILA clones, ~1.7GB) and wheels/ (prebuilt flash-attn 2.5.8, 116MB) — third-party build-context vendoring, reconstructible from commands documented in that task's Dockerfile. No policy checkpoints are included. Differences between tasks (pi05 is the deepest pilot; navid/navila are uncalibrated scaffolds blocked on Matterport3D-gated scenes) are stated in the README rather than papered over.
Ready for review.