Add bounded full-bag mapping gate

[rsasaki0109]

What changed

• Add the portable FullBagMappingState admission contract for source-bound bounded full-bag mapping.
• Add the feature-gated rosbag2_full_bag_mapping runner with explicit source/episode/chunk limits, PointCloud2 chunk reassembly, registered clock correction, accepted root-to-sensor frame paths, full selected-stream ICP/pose graph, root-frame TSDF, embedded glTF receipt, and fail-closed JSON/HTML/manifest output.
• Integrate the mapping state into Mission Cockpit so blocked or mismatched full-bag mapping cannot be reported as admitted.
• Update roadmap, real-data acceptance documentation, changelog, and implementation note.

Acceptance evidence

The canonical bag matched SHA-256 b00d31e25dc0b53cba89cfbe16e5b118079c514a1d8c6f4089fac9c0e3ffd7c8. The no-artifact run intentionally exits 2 with mapping_admitted:false and seven blockers because real source-bound calibration evidence is not present. A wrong-SHA probe also remains fail-closed, and Mission Cockpit propagates the mapping blockers.

External receipts:

• /media/sasaki/aiueo/spatialrust-results/v1-3/145k-full-bag-mapping-v3/
• /media/sasaki/aiueo/spatialrust-results/v1-3/145k-full-bag-mapping-validation-probe-v1/
• /media/sasaki/aiueo/spatialrust-results/v1-3/145k-mission-cockpit-v3/

Checks

• cargo fmt --all -- --check
• cargo test --workspace
• cargo clippy --workspace --all-targets -- -D warnings
• cargo test --workspace --all-features --no-run
• cargo clippy --workspace --all-features --lib -- -D warnings
• canonical, wrong-input, and Mission Cockpit JSON gate probes
• generated dashboard JavaScript syntax checks