fix: Fix profile<->provider logic: lock a profile to its subscription provider/models while the agent can still select any pr

[andrei-hasna]

Objective

Fix profile<->provider logic: lock a profile to its subscription provider/models while the agent can still select any provider (clean redesign). — Start a goal plan for this task and drive it node by node (required). Investigate the current codewith implementation first and cite file:line. Build and test on remote Blacksmith ONLY (never compile locally). Keep cargo fmt, clippy -D warnings, and prettier clean. Land a PR into hasna/codewith main.

Verification

• install: pass

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Run run_b8b622729296 · backend codewith · task inline
🏭 Generated by @hasnaxyz/factory

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