feat(research): add mana-research service — Phase 1 + 2

New Bun/Hono service on port 3068 that bundles many web-research providers
behind a unified interface for side-by-side comparison. All eval runs
persist in research.* (mana_platform) so quality can be reviewed later.

Providers (Phase 1+2):
  search:  searxng, duckduckgo, brave, tavily, exa, serper
  extract: readability (via mana-search), jina-reader, firecrawl

Endpoints:
  POST /v1/search, /v1/search/compare       — single + fan-out
  POST /v1/extract, /v1/extract/compare     — single + fan-out
  GET  /v1/runs, /v1/runs/:id               — history
  POST /v1/runs/:run/results/:id/rate       — manual eval
  GET  /v1/providers, /v1/providers/health  — catalog + readiness

Auto-routing: when `provider` is omitted, queries are classified via regex
(fast path, 0ms) with optional mana-llm fallback, then routed to the first
available provider for that query type (news → tavily, academic → exa,
semantic → exa, etc.).

Credits: server-key calls go through mana-credits reserve → commit/refund
so failed provider calls don't charge the user. BYO-keys supported via
research.provider_configs (UI arrives in Phase 4).

Cache: Redis with graceful degradation (1h TTL for search, 24h for
extract). Pay-per-use APIs only — no subscription-gated providers.

Docs: docs/plans/mana-research-service.md + docs/reports/web-research-capabilities.md

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

docs/PORT_SCHEMA.md

@@ -26,7 +26,8 @@
 > - mana-mail `3042`
 > - mana-sync `3050`
 > - mana-credits `3061`, mana-user `3062`, mana-subscriptions `3063`,
->   mana-analytics `3064`, mana-events `3065`
+>   mana-analytics `3064`, mana-events `3065`, mana-research `3068`
+>   (new 2026-04-17, Bun/Hono, public: `research.mana.how`)
 >
 > **Not deployed:** `mana-voice-bot` (default port `3024`, no scheduled
 > task, no cloudflared route, no launchd plist).