feat(eltex): three proxy models in /model, anth-glm-5.3 by default

Admins now give every key three models. ai-eltex maps them to the
picker slots:
- opus (default): anth-glm-5.3 - glm-5.3 on the Z.ai Anthropic
  endpoint: images via analyze_image, effort works, 1M window;
- sonnet: zai-glm-5.3 - glm-5.3 on the OpenAI endpoint, no images or
  effort, 200K. Two keys get it as zai-glm-5.3-2-2 (zai-glm-5.3 is 403
  for them), so the name is matched exactly or by prefix;
- haiku: zai-glm-5.3-flash - fast, sees images itself, no effort,
  200K; Claude Code also uses this slot for background tasks.
A missing zai/flash model falls back to the default one.

Model name is anth-glm-5.3 again: with anth-glm-5.3-5 the auto-logout
would drop every saved key, since no key has that name now.

Context window is per model instead of a global
CLAUDE_CODE_MAX_CONTEXT_TOKENS=1000000: [1m] only on anth-glm-5.3
(Claude Code strips the suffix before the API call), 200K for the
others, otherwise a long flash/zai session would hit "Prompt exceeds
max length" instead of auto-compacting.

Checked on all 6 pilot keys (19.10): default model reads a png via
Read + analyze_image; sonnet/haiku answer with 200K windows; effort
low on anth-glm-5.3 = 68 output tokens (max ~3500).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

EFFORT_MAPPING.md

@@ -173,4 +173,5 @@ ai-deepseek                  # без флага - использовать ур
 - У GLM осмысленно выбирать только `low`, `high` (или `xhigh`) и `max`.
 - `ai-eltex`: с 09.10 прокси пропускает effort для `anth-glm-5.3`, маппинг тот же, что у `ai-glm`
   (на стороне Z.ai). Как и `ai-glm`, стартует на `max` через CLI `--effort`, `AI_EFFORT=high ai-eltex`
-  работает. У `ai-eltex-qwen` прокси effort игнорирует, `/effort` и `AI_EFFORT` там ни на что не влияют.
+  работает. У `zai-glm-5.3` и `zai-glm-5.3-flash` (тоже в `/model` у `ai-eltex`, 19.10) effort не работает:
+  low и max дают одинаковый расход. У `ai-eltex-qwen` прокси effort игнорирует, `/effort` и `AI_EFFORT` там ни на что не влияют.