Rebrand zeltrin to joltrin

[gerardrecinto]

Summary

• Repository renamed on GitHub from zeltrin to joltrin (trademark conflict); this PR completes the in-repo migration.
• Two-commit hygiene: file/dir moves isolated from content edits so git blame and git log --follow stay intact.
• Content replaced case-preserving across all 703 matched files (module paths, identifiers, docs, CI workflow image names, WASM globals).

Test plan

• go build ./... clean across all 8 modules (root, jsondb, incfs, search, infs, ai, adapters/redis, adapters/cassandra)
• go vet ./... clean across all 8 modules
• GOOS=js GOARCH=wasm go build clean for demo and demo-agents
• go test ./... full suite passing, 0 failures, across all 8 modules
• Zero residual zeltrin references (case-insensitive) repo-wide
• git log --follow / git blame verified intact through the asset renames