chore: add npm keywords for registry search discoverability

[andrei-hasna]

Summary

@hasna/emails (currently 1.3.7 on the registry) publishes with an empty
keywords array, so it does not surface in npm registry search results.
This adds a keyword list to the published root manifest.

Keywords added, derived from the package's own description field and
README.md (verified against the file content, not invented): email,
smtp, ses, resend, cloudflare, sqlite, self-hosted, cli,
mcp, ai, coding-agent.

Metadata-only diff — no version bump, no other files touched, no build
output changed.

Test plan

• python3 -c "import json; json.load(open('package.json'))" — valid JSON
• Diff scoped to a single 13-line keywords insertion in package.json, nothing else
• Staged secrets scan (mandatory pattern set) — 0 matches
• Repo's own node scripts/scan-staged-secrets.mjs — exit 0, clean
• Not merged, published, or version-bumped by this PR — left for the release owner

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[andrei-hasna]

[REVIEW] GO — #200 @ c4fa1b0 — lens: correctness+security+gates, reviewer unresolved-account003 (1 of 1)

What I ran:

• bun install — exit 0. Setup only; not counted as the repository test gate.
• bun run test — exit 0: 4,289 pass, 156 skip, 0 fail across 288 files (4,445 tests; 20,928 expect calls).
• The repository declares no typecheck script, so no typecheck gate was invented or run.

What I read:

• git log --oneline origin/main..HEAD at base 2dbc7ee0f66babe34ee6e45d7a20af69c5de52e5 and head c4fa1b0ecd77155dd6359e9bc056e22c3e846188.
• git diff origin/main...HEAD --stat.
• The complete diff for every changed file: package.json only, adding 13 lines of npm keyword metadata.
• The full surrounding package.json at both the PR head and origin/main.

Blocking P0/P1 findings: none. The change is package-discovery metadata only and introduces no runtime, authorization, credential, data-integrity, mutation, migration, or rollback path.

Non-blocking follow-ups: none.