feat(import): support Hermes Agent JSONL

[wbugitlab1]

Summary

• Adds Hermes Agent flat JSONL role handling to import-jsonl replay parsing.
• Converts Hermes user, assistant tool-call, and tool result rows into existing observation types.
• Documents Claude Code or Hermes JSONL support in replay UI and CLI copy.

Closes #297.

Verification

• corepack pnpm exec vitest run test/replay.test.ts test/replay-import-key.test.ts
• corepack pnpm run lint
• corepack pnpm run build
• corepack pnpm test
• semgrep scan --config p/default --error --metrics=off .
• gitleaks protect --staged --redact