feat(extractors): add 17 job source extractors and cross-source dedup

Adds extractor packages: arbeitnow, ashby, careerjet, fourdayweek,
greenhouse, himalayas, jobicy, jooble, lever, reed, remoteok, remotive,
themuse, usajobs, weworkremotely, workday — each with manifest, package
metadata and README.

Pipeline / shared:
- shared/job-fingerprint: stable hash for cross-source dedup, with tests
- discover-jobs: dedup via fingerprint and richer per-source merging
- jobs repository: fingerprint-aware upsert / lookup
- settings-registry, settings types/routes, demo-defaults: knobs for the
  new sources
- shared extractors index: register the new manifests
- location-support, profiles route: small fixes for the new sources

Tooling:
- scripts/smoke-extractors.ts to sanity-check each source locally
- scripts/jobber-cron-{cherepaha,dobkin}.env.example: per-host cron
  templates (CHANGEME placeholders only)
- .env.example: documented env vars for the new extractors
- .gitignore: ignore extractors/*/storage/ runtime caches (was ukvisajobs only)

Co-authored-by: Cursor <cursoragent@cursor.com>

.env.example

@@ -97,3 +97,116 @@ ADZUNA_APP_KEY=
 # =============================================================================
 # Filter for remote-only jobs (default: 0 = disabled)
 # JOBSPY_IS_REMOTE=0
+
+# =============================================================================
+# USAJOBS API (US federal jobs) - optional, US-only
+# =============================================================================
+# Register at https://developer.usajobs.gov/APIRequest/Index
+# USAJOBS requires a User-Agent that is a real contact email (per their TOS).
+# Leave unset to disable the source.
+# USAJOBS_API_KEY=
+# USAJOBS_USER_AGENT=you@example.com
+# USAJOBS_MAX_JOBS_PER_TERM=100
+
+# =============================================================================
+# Jobicy (remote jobs feed) - optional, no auth
+# =============================================================================
+# Public JSON endpoint, capped at 50 results per call.
+# JOBICY_MAX_JOBS_PER_TERM=100
+
+# =============================================================================
+# The Muse (jobs API) - optional, API key recommended
+# =============================================================================
+# https://www.themuse.com/developers/api/v2 — works without a key but is
+# heavily rate-limited. Set THEMUSE_API_KEY for higher quotas.
+# THEMUSE_API_KEY=
+# THEMUSE_MAX_JOBS_PER_TERM=100
+
+# =============================================================================
+# Jooble (aggregator API) - optional
+# =============================================================================
+# Sign up at https://jooble.org/api/about for an API key.
+# JOOBLE_API_KEY=
+# JOOBLE_MAX_JOBS_PER_TERM=100
+
+# =============================================================================
+# Careerjet (publisher API v4) - optional
+# =============================================================================
+# Register at https://www.careerjet.com/partners/api/ — declare API key + server IP(s).
+# CAREERJET_AFFID=your_api_key
+# CAREERJET_REFERER=https://your-site.com/path-to-job-search/
+# CAREERJET_USER_IP=203.0.113.1
+# Optional override for the required user_agent query param:
+# CAREERJET_USER_AGENT=Mozilla/5.0 ...
+# CAREERJET_MAX_JOBS_PER_TERM=100
+
+# =============================================================================
+# Reed.co.uk (UK jobs API) - optional, UK-only
+# =============================================================================
+# Register at https://www.reed.co.uk/developers/jobseeker for an API key.
+# REED_API_KEY=
+# REED_MAX_JOBS_PER_TERM=100
+
+# =============================================================================
+# Remote OK (remote jobs feed) - optional, no auth
+# =============================================================================
+# Public single-shot JSON feed at https://remoteok.com/api. We filter
+# client-side by your search terms (matched against position + tags).
+# Per Remote OK's TOS, link back to the original posting URLs when republishing.
+# REMOTEOK_MAX_JOBS_PER_TERM=100
+
+# =============================================================================
+# Remotive (remote jobs feed) - optional, no auth
+# =============================================================================
+# Public JSON API at https://remotive.com/api/remote-jobs?limit=N&search=term.
+# Each search term is sent as the `search` parameter.
+# REMOTIVE_MAX_JOBS_PER_TERM=100
+
+# =============================================================================
+# Arbeitnow (multi-ATS aggregator) - optional, no auth
+# =============================================================================
+# Public JSON API at https://www.arbeitnow.com/api/job-board-api?page=N.
+# Aggregates from Greenhouse, SmartRecruiters, Join, TeamTailor, Recruitee,
+# and Comeet. No server-side search; filtering is done client-side.
+# ARBEITNOW_MAX_JOBS_PER_TERM=100
+
+# =============================================================================
+# Himalayas (remote jobs feed) - optional, no auth
+# =============================================================================
+# Public JSON API at https://himalayas.app/jobs/api?limit=N&offset=M.
+# No server-side search; filtering is done client-side by title + categories.
+# HIMALAYAS_MAX_JOBS_PER_TERM=100
+
+# =============================================================================
+# We Work Remotely (RSS feed) - optional, no auth
+# =============================================================================
+# Public RSS at https://weworkremotely.com/remote-jobs.rss (all categories).
+# Single fetch; filtering is done client-side by title + skills + category.
+# WEWORKREMOTELY_MAX_JOBS_PER_TERM=100
+
+# =============================================================================
+# 4 Day Week (reduced-schedule jobs) - optional, no auth
+# =============================================================================
+# Public JSON API at https://4dayweek.io/api/jobs?page=N.
+# Paginated; filtering is done client-side by title + tech stack.
+# No job description in listings; links to 4dayweek.io for details.
+# FOURDAYWEEK_MAX_JOBS_PER_TERM=100
+
+# =============================================================================
+# Public ATS sources (Lever / Ashby / Greenhouse) - optional
+# =============================================================================
+# Comma- or newline-separated company slugs. The slug is the path segment used
+# in each provider's public job board, e.g. `lever.co/some-company` → "some-company".
+# LEVER_COMPANIES=netflix,figma
+# ASHBY_COMPANIES=ramp,linear
+# GREENHOUSE_COMPANIES=stripe,airbnb
+
+# =============================================================================
+# Workday (public career sites) - optional
+# =============================================================================
+# Newline- or comma-separated entries. Each entry is either:
+#   1) A career-site URL we'll auto-parse, e.g.
+#      https://nvidia.wd5.myworkdayjobs.com/en-US/NVIDIAExternalCareerSite
+#   2) A JSON object with explicit fields:
+#      {"company":"NVIDIA","tenantUrl":"https://nvidia.wd5.myworkdayjobs.com","tenant":"nvidia","site":"NVIDIAExternalCareerSite","locale":"en-US"}
+# WORKDAY_TENANTS=