Add SnowSignals TrendVane (market-phase / regime data source)

[snowkidind]

Adds SnowSignals TrendVane to Market Data & Data Sources.

It's a multi-timeframe crypto market-phase (regime) API: it classifies each currency/timeframe into one of 12 phase states (both closed-bar and intra-bar), and ships a separate BTC-derived resolution model — successor-phase transition probabilities, trend-continuation rates and reward-vs-drawdown (MFE/MAE), each figure carrying its sample count. It reports market state, not trade signals.

• Site: https://snowsignals.io
• OpenAPI: https://snowsignals.io/v1/openapi.json
• Docs repo: https://github.com/snowkidind/snowsignals-mcp

Metadata and the resolution stats are free and need no account (a genuine free tier); live phase reads are metered. Fits alongside the existing regime/backtest data sources in that section (Backtesting Arena, PreReason). One entry, appended in section order per the contributing guidelines.

[wilsonfreitas]

Thanks for contributing! Please move this entry to Commercial & Proprietary Services, since the linked repository provides connection documentation rather than the analytics implementation. Please also provide accessible public pricing, free-endpoint limits (or explicitly document no limits), and a working example response from phase_resolution_stats so we can verify useful permanent access without payment information. The site, docs, and OpenAPI returned 403 during review. Please shorten the description to the service’s core functionality and free/paid distinction.

[snowkidind]

Thanks for the review — all addressed:

1. Moved to Commercial & Proprietary Services and shortened to core functionality + the free/paid distinction (just pushed).
2. 403 resolved. The zone had a Cloudflare AI-bot rule challenging automated fetchers; it's now set to allow. https://snowsignals.io, /docs, and /v1/openapi.json all return 200 to plain crawlers now — please re-check when convenient. If uptime is a concern, there's a public status page: https://snowsignals.statuspage.io/ (currently all systems operational).
3. Pricing (public, no account): free and unmetered — metadata (GET /v1/api/phases) and the phase-resolution model (GET /v1/api/phase/resolution-stats); no rate limit beyond ordinary abuse protection. Metered: live phase reads at a base $0.0023/row (a "row" = one currency × timeframe), tiered down for bulk / up to ~$0.0029 for a single-row request; prepaid balance, HTTP 402 when out of credits. Pricing is also served live in the pricing block of /v1/api/phases.
4. Example phase_resolution_stats response (BTC, 2022–2026, closed boundaries; every figure carries its count n):

{
  "scope": "BTC only, 2022-01-01 -> 2026-07-01, closed boundaries",
  "rewardDrawdown": { "Breaking":     { "mfe": 2.2, "mae": 1.4, "n": 447 },
                      "Establishing": { "mfe": 1.1, "mae": 1.0, "n": 1406 } },
  "transitionMatrix": { "BRK>EST": { "bull": 87, "bear": 89 },
                        "CON>BRK": { "bull": 50, "bear": 55 } }
}

(Full response is ~16 KB across all timeframes and phases.)

Happy to adjust anything else.

[snowkidind]

Rebased on the latest main to clear the merge conflict (new entries had landed in the same section). Down to a single commit adding the one row under Commercial & Proprietary Services; validate CI is green. Ready whenever you'd like to take another look.