v0.12.208 — Fix non-ASCII reasoning header crashing paid responses

Stop non-English prompts from crashing paid responses via the x-clawrouter-reasoning header.

• Non-ASCII routing reasoning crashed res.writeHead after settlement (src/proxy.ts). The routing reasoning string embeds matched keywords from the multilingual lists in src/router/config.ts (Cyrillic, CJK, …). Debug headers are on by default, so for e.g. Russian prompts the raw Cyrillic keywords landed in the x-clawrouter-reasoning response header and Node rejected the write with ERR_INVALID_CHAR — after the upstream call had completed and the x402 payment had settled. The client never received the body and retried, signing a fresh payment each round: a paid retry loop. Header values are now percent-encoded outside printable ASCII (sanitizeHeaderValue, reversible via decodeURIComponent), and as defense in depth a rejected writeHead sanitizes all header values and still delivers the paid body instead of throwing. (Test: proxy.reasoning-header.test.ts, 13 cases, including a live Russian-prompt repro through classifyByRules validated against Node's validateHeaderValue.)
• CLAWROUTER_DEBUG_HEADERS=off|false|0 — new env kill switch for the x-clawrouter-* debug headers, for clients that can't set the per-request x-clawrouter-debug: false header. Comments claiming the headers were "opt-in" corrected (they are on by default).

---

npm: @blockrun/clawrouter@0.12.208