chore: lock final Luna memory stack

[dajiaohuang]

Closes #40.

Refreshes the local SagaSmith compatibility lock to the final post-Luna domain revisions:

• Core d04ecca3cb4b3d5d1d6a232d1481974c91fbb710
• D&D d114c42e09be4b7e32a4984a147e87fd70129829
• CoC 323b08c3e210e4f351c03a80714d54068438242b
• Narrative e61039aaa7715d785917d066404bcbe545c32de5

The lock remains explicitly non-published: compatibility-lock-not-published.

This refresh also closes a real Host/domain compatibility gap found only after loading the final revisions:

• carry explicit modern exposure_handle values through the CoC and D&D stdio conversation flows
• upgrade the isolated NPC worker from proposal v4 to v5
• require content_mode on every utterance segment and allowed evidence for grounded, deceptive, or uncertain factual speech
• keep private intent and proposal internals out of publication

Local verification:

• uv run ruff check nanobot tests --select F
• focused lock/NPC suite: 33 passed
• real CoC and D&D stdio NPC conversation flows passed
• full suite: 5413 passed, 58 environment-gated skips
• git diff --check
• independent gpt-5.6-luna v5/lock review passed, including negative validation and privacy checks