.gitignore + docs: drop stale db* rule; refresh Latest Tag to v1.26.28

The bare `db*` .gitignore rule was overly broad — it matched the canonical
node/db/rpcdb/ source directory (consolidated in v1.26.28). Previous PRs
needed `git add -f` to land files there. No code references in-repo ./db/
runtime path; runtime DB lives under ~/.lux/ per the canonical operator
convention.

LLM.md + CLAUDE.md updated to reflect actual current main tag.

.gitignore

@@ -31,8 +31,6 @@ tmp/
 
 *.pb*
 
-db*
-
 *cpu[0-9]*
 *mem[0-9]*
 *lock[0-9]*