Update the experience mining prompt to output links alongside journal
entries. The LLM now returns a "links" array per entry pointing to
existing semantic nodes. Rust code creates the links immediately after
node creation — new nodes arrive pre-connected instead of orphaned.
Also: remove # from all key generation paths (experience miner,
digest section keys, observed transcript keys). New nodes get clean
dash-separated keys.
Co-Authored-By: Kent Overstreet <kent.overstreet@linux.dev>