Install engine: info + add with content-digest verification

[jal-co]

Tracks the read + install path (PLAN.md Milestones 1,3,4). Distinct from #5 (Tegami), #6 (login), #7 (publish).

v0 shipped (branch feat/install-verify):

• modulora info @user/name[@version] — metadata, files, published digest, --json
• modulora add @user/name[@version] — fetch, recompute content digest locally and compare to the published digest, write plan, write files
• Fail closed on digest mismatch (refuse unless --force); prompt on unverifiable
• Safe path resolution (no escape); src/ detection; --dry-run/--yes/--force/--json/--cwd
• Server exposes meta.contentSha256 on /r/; digest canonical across publish → serve → CLI
• Installer only writes files — never runs a script

Next:

• search against the public API
• diff + update (three-way, never discard local edits)
• modulora.lock (source, version, digest, local hashes)
• Signature/attestation + revocation (Milestone 2, needs spec CLI: authenticate with modulora.dev (modulora login) #6)
• Cross-platform CI + malicious-registry fixtures

[jal-co]

Install receipts shipped: add now POSTs a receipt (best-effort, 4s timeout, never blocks the install) with the locally-computed digest; the server re-verifies against the published digest and attributes to the signed-in user. Verified E2E: receipt row lands verified=true attributed to the installing account.

[jal-co]

modulora search shipped against the new public /api/search endpoint (approved+public only, --json supported). Remaining on this issue: diff/update, modulora.lock, signatures/revocation (needs spec#6), cross-platform CI.

[jal-co]

Lockfile + verify/diff/update shipped: modulora.lock (version, digest, per-file hashes), verify (dirty detection, exit 1), three-way diff, and update (digest-verified, conflict-refusing, never discards local edits — dirty files keep their flag through updates). Full lifecycle verified E2E. Remaining: signatures/revocation (needs spec#6), cross-platform CI, malicious-registry fixtures.