Rollup of builds 147-154 since v1.0-build146.
Captcha (legacy fallback path):
- 147: fix the legacy captchaNotRobot.* auto-solver (BOT since 2026-05-15) — the discriminator was HTTP/2 request header ORDER; pin the real Safari WKWebView order.
- 148: port amurcanov's v2 slider solver (3-metric consensus + Bezier cursor).
- 149: undocumented forceLegacyCaptcha backup-JSON test switch (default off; no prod effect).
Legacy TURN-credential minting — fixes the "stuck at ~20 connections" ceiling on the legacy fallback:
- 150: cap conn-driven cold-start credpool fetches (no empty-pool over-fetch).
- 151: use working VK app secrets + drop 3 app_ids that lack the Calls method (fixes error_code 10 "Internal server error" on the legacy mint).
- 152-153: mint a DISTINCT anonymous credential per fetch — fresh per-fetch device_id + a fresh cookie session per fetch (VK keys the legacy anon token on the cookie session, not device_id). Removes the ~20-conn ceiling on the legacy path.
Diagnostics:
- 154: show App-Group storage facts on the empty in-app log screen + batch-drain the Go log-file writer.
The primary captcha-free path (VK Calls, client_id 8093730) is unchanged — these changes harden the legacy fallback.