[zenith-root] chore: sync Lotus Next real Bamboo acceptance

[bigduu]

Summary

• advance only the lotus-next submodule pointer to the accepted real-Bamboo browser baseline
• preserve every other root file and submodule pointer unchanged
• integrate the separately reviewed provider fixture, exact-source runtime harness, and full browser-to-Bamboo round-trip gate

Submodule Updates

Submodule	Old	New	Rationale
lotus-next	4fa46103d6e323f030cbaaa6c9e48a5e0467c446	3decd7d3d51ebc91f13770b5d102263cd6c65c6d	Includes merged PRs #44, #45, and #46: deterministic loopback provider, isolated exact-revision Bamboo runtime, and a production Chromium chat/persistence/rehydration round trip through real Bamboo.

The target is the current bigduu/lotus-next main. PR #46 passed Node 22, Node 24, and Real Bamboo / Node 22; the real job built Bamboo 655732e24561b09869b7e97ab11bba01cf9bc4df from clean source, passed 2/2 real tests, and uploaded reviewed redacted evidence.

Test Plan

• verify the staged/root diff contains only the lotus-next mode-160000 gitlink
• verify all 33 non-lotus-next root tree entries are byte-identical to origin/main
• verify 3decd7d3d51ebc91f13770b5d102263cd6c65c6d is current Lotus Next main and contains [zenith] chore: bump Bamboo and Lotus pointers for #793 #44/[zenith] chore: bump Bamboo pointer for #736 #45/chore: bump bamboo pointer for #744 #46
• verify upstream Issues chore: bump lotus for Project workspace assignment #43/chore: sync Bamboo submodule pointer #42/chore: sync Bodhi lockfile pointer #39 are closed and Roadmap Done
• verify upstream PR chore: bump bamboo pointer for #744 #46 exact-head Node 22, Node 24, and Real Bamboo checks are successful
• git diff --check
• Zenith Submodule Guard

Closes #179