refactor(cli): extract provider commands into commands/provider module

Move all provider-related functions, helpers, constants, and tests from
the monolithic run.rs (~2,700 lines) into a dedicated
commands/provider.rs module. This is PR3 of the CLI refactor series
(issue #2304).

The extraction follows the same pattern established in PR2 (gateway):
- Self-contained module with own imports
- pub use re-exports in run.rs so callers (main.rs) are unchanged
- Inline #[cfg(test)] mod tests

Signed-off-by: Varsha Prasad Narsing <vnarsing@nvidia.com>
Signed-off-by: Varsha Prasad Narsing <varshaprasad96@gmail.com>

Author: varshaprasad96

crates/openshell-cli/src/commands/mod.rs

@@ -3,3 +3,4 @@
 
 pub mod common;
 pub mod gateway;
+pub mod provider;