feat: bounded 64 KiB headless goals with offline capability advertisement

[SonAIengine]

General transport fix: complete structured host requests can exceed the old 16 KiB goal limit. Raise headless goal bound to 64 KiB without truncation; advertise exact bound in run help. REPL, permissions, planner context and call budgets remain unchanged. Tests: CLI suite passes; new ASCII/Korean/emoji boundaries and local mock-provider intact 64 KiB request/approval tests pass; clippy all CLI targets passes. No live LLM or production training. Platform companion negotiates support, retaining 16 KiB for old binaries.

[SonAIengine]

Linux release build of ae7ffe8 completed. SHA256 316aced572a0c823cbd1f9c2091f215c9366f81326e11323f53b366cf2eaf455. Offline platform inspection confirms protocol 0.1, inference_limits=true, request_profiles=true, max_goal_bytes=65536. Windows keeps 16384 due OS argv constraints and advertises its own bound. No production binary switch yet. Platform companion: SonAIengine/expharness#167 (exact-head server CI passed).

[SonAIengine]

Exact Linux release 316aced572a0c823cbd1f9c2091f215c9366f81326e11323f53b366cf2eaf455 passed one isolated real DeepSeek/XGENy atomic-write canary: run-cbe230c69eb5da95d905509e937dd350, verified JSON status=ok and native completion proof. QA artifact root /dev/shm/request-bound-release-canary-i3c0d6jq. One adapter invocation (not a claim of one provider inference), no participant training or production project writes. Production binary remains unchanged pending final required CI.