build: bundle with tsup — 5-file dist, lazy DLP chunk

[cdot65]

Summary

Replaces raw tsc emit with tsup bundling. dist/ drops from ~200 ESM files (2.5MB) to 5 files (355KB unpacked; npm pack: 7 files, 74.7kB).

Changes

• tsup.config.ts: dual entry (library index + CLI bin), esm, es2022, splitting on (keeps the src/dlp dynamic import as a separate lazy chunk), dts for the library entry, all deps external
• build = tsup; build:tsc kept as escape hatch; CI typecheck still tsc --noEmit (unchanged)
• CLAUDE.md build line updated

Verification

• Shebang preserved; --version works; startup 0.06s
• Lazy chunk: dlp generate --output json loads dlp chunk on demand, JSON parses clean
• Library entry: 18 exports importable from dist/index.js; index.d.ts generated
• Dockerfile unaffected (runs pnpm run build, copies dist/)
• 690/690 tests; lint + tsc clean

Checklist

• Gates green
• Changeset (patch)

Closes #271