feat: add alibaba coding plan as provider

[joshuachong]

Summary

• Fixes Integrate Alibaba Coding Plan Models #418 and replicates feat: add Alibaba Coding (DashScope Intl) provider with 8 models #747 for correct integration, documentation and model specs.
• Adds Alibaba Coding Plan (International) subscription as a model provider into OpenFang provider list. Coding Plan is a subscription based and not pay-per-token service
• Integrating using reference from Alibaba Coding Plan's OpenClaw integration

Notes:

• API Key format: sk-sp-xxxxx (plan-specific, different from pay-as-you-go sk-xxxxx)
• Base URL: https://coding-intl.dashscope.aliyuncs.com/v1
• Subscription: $50/month Pro plan with quota limits (90K requests/month, 45K/week, 6K per 5 hours)

Model Specifications

Model ID	Display Name	Tier	Context	Max Output	Vision	Tools	Cost
alibaba-coding-plan/qwen3.5-plus	Qwen 3.5 Plus	Smart	1,000,000	65,536	✅	✅	$0
alibaba-coding-plan/qwen3-max-2026-01-23	Qwen 3 Max	Frontier	262,144	65,536	❌	✅	$0
alibaba-coding-plan/qwen3-coder-plus	Qwen 3 Coder Plus	Smart	1,000,000	65,536	❌	✅	$0
alibaba-coding-plan/qwen3-coder-next	Qwen 3 Coder Next	Frontier	262,144	65,536	❌	✅	$0
alibaba-coding-plan/glm-5	GLM-5 (Zhipu)	Frontier	202,752	32,768	❌	✅	$0
alibaba-coding-plan/glm-4.7	GLM-4.7 (Zhipu)	Smart	202,752	32,768	❌	✅	$0
alibaba-coding-plan/kimi-k2.5	Kimi K2.5 (Moonshot)	Smart	262,144	32,768	✅	✅	$0
alibaba-coding-plan/MiniMax-M2.5	MiniMax M2.5	Smart	204,800	32,768	❌	✅	$0

Changes

• Added Alibaba Coding Plan as constants and model_catalog
• 8 model entries added as part of Alibaba Coding Plan support
• Added pattern matching for Alibaba Coding Plan on metering since this is a subscription-based model and not pay-per-token
• Updated documentation for new provider

Testing

• cargo clippy --workspace --all-targets -- -D warnings passes
• cargo test --workspace passes
• Live integration tested (if applicable)

Security

• No new unsafe code
• No secrets or API keys in diff
• User input validated at boundaries

[jaberjaber23]

Reviewed and approved. This PR has merge conflicts with recent changes on main. Please rebase onto current main and we will merge it.