fix: auto-route Ollama Cloud models to ollama.com when API key is set

[corvid-agent]

Summary

• Cloud models (e.g. qwen3-coder:480b-cloud) now auto-route to https://ollama.com when OLLAMA_API_KEY is configured, instead of going through localhost:11434 where the local daemon can't forward auth
• fledge ai status now shows API key source (env/config/not set) and whether cloud routing is active
• fledge ai use prompts for API key when selecting a cloud model without one configured
• fledge config list now shows env var override indicators for OLLAMA_HOST and OLLAMA_API_KEY
• Empty API keys are filtered as None — prevents sending Authorization: Bearer with no token

Host resolution precedence

1. OLLAMA_HOST env var (explicit user override — always wins)
2. Non-default config host (user explicitly configured a custom endpoint)
3. Cloud host (https://ollama.com) when API key present AND model is cloud
4. Default localhost (http://localhost:11434)

Test plan

• 844 unit tests pass
• is_cloud_model correctly matches -cloud variants
• resolve_effective_host routes cloud models to ollama.com with key
• Cloud model stays local when no key is present
• Explicit OLLAMA_HOST env var overrides cloud auto-routing
• Custom config host overrides cloud auto-routing
• Non-cloud models stay local even with API key set
• build_provider errors early when cloud model lacks API key
• Empty API key string treated as missing

Closes #380

🤖 Generated with Claude Code

[github-actions]

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CI Summary

Check	Status
Dependency Audit	✅ Passed
Integration (3 OS)	❌ failure
Lint (fmt + clippy)	❌ failure
Spec Validation	❌ failure
Tests (3 OS)	✅ Passed

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[corvid-agent]

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[corvid-agent]

All three CI failures addressed in 3c89cdd:

• Lint (fmt): Ran cargo fmt — reformatted function signatures in ai.rs, config_cmds.rs, llm.rs
• Lint (clippy): Replaced format!(" (auto-routed to cloud)") with " (auto-routed to cloud)".to_string() in ai.rs:175
• Spec Validation: Documented 3 new exports (DEFAULT_OLLAMA_CLOUD_HOST, is_cloud_model, resolve_effective_host) in specs/llm/llm.spec.md — strict mode now passes with 0 warnings

Verified locally: cargo fmt --check ✅, cargo clippy -D warnings ✅, specsync check --force --strict 0 warnings ✅

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Superseded by updated review.

[github-actions]

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CI Summary

Check	Status
Dependency Audit	✅ Passed
Integration (3 OS)	✅ Passed
Lint (fmt + clippy)	✅ Passed
Spec Validation	✅ Passed
Tests (3 OS)	✅ Passed

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[corvid-agent]

CI failures resolved in 3c89cdd:

• Lint (fmt): Reformatted multi-line function signatures to match rustfmt style
• Lint (clippy): Replaced format!(" (auto-routed to cloud)") with " (auto-routed to cloud)".to_string() (clippy::useless_format)
• Spec Validation: Documented 3 new exports (resolve_effective_host, is_cloud_model, DEFAULT_OLLAMA_CLOUD_HOST) and added cloud routing invariants + error case to the LLM spec

All checks now passing — spec-check, lint, tests (3 OS), audit, and integration (3 OS). ✅

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