Add first-class Ollama provider

[TheGreatAxios]

Summary

• Adds Ollama as a first-class keyless provider with an editable local server URL.
• Discovers installed models dynamically through the OpenAI-compatible /v1/models endpoint and handles unavailable, empty, and malformed responses without crashing.
• Reuses the existing Interchange OpenAI-compatible adapter and documents the setup and recovery flow.

Verification

• bun run check passes
• git diff --check passes
• Provider switching tests confirm stale API keys are never sent to or persisted for Ollama

Fixes CL-7330

[linear-code]

CL-7330

[TheGreatAxios]

Critic lens · clean

The branch adds first-class keyless Ollama setup and dynamic /v1/models discovery through the existing OpenAI-compatible adapter.

No blocking correctness findings remain. Provider switching clears stale credentials in src/tui/provider-setup.ts:1593, and the submit boundary independently omits credentials for keyless Ollama in src/tui/provider-setup-submit.ts:56; regression tests cover both sequences.

[TheGreatAxios]

Primary review · clean

The branch adds a keyless Ollama provider with root-to-/v1 projection, dynamic model discovery, nonfatal recovery states, tests, and documentation.

No findings. origin/main...HEAD contains one scoped commit and 17 Ollama-related files; bun run check, git diff --check, and all GitHub checks pass. GitHub does not allow an author to approve their own PR, so this verdict is posted as a review comment.