fix(cron): add standalone cron daemon mode

[alaamohanad169-ship-it]

What does this PR do?

Adds hermes cron daemon command to run the cron scheduler as a standalone process, independent of the gateway.

Problem: Cron jobs don't execute on systems where the gateway isn't running (Windows without service installation, headless servers, etc.). The cron scheduler only runs inside the gateway process, so if the gateway isn't started, cron jobs never fire.

Solution: New hermes cron daemon command that runs the same tick loop as the gateway's internal cron ticker, but as a standalone process.

Changes Made

• hermes_cli/cron.py: Added cron_daemon() function that runs the cron tick loop with signal handling
• hermes_cli/main.py: Added daemon subcommand parser with --interval option (default 60s)

How to Test

1. Create a cron job:

   hermes cron create "* * * * *" "Test job - just print hello" --name test-daemon
   

2. Start the cron daemon:

   hermes cron daemon --interval 60
   

3. Verify the job executes (check hermes cron list for last_run_at)

4. Stop with Ctrl+C

Related Issue

Fixes #41037 (Cron jobs never execute: last_run_at always null after manual trigger)

Type of Change

• 🐛 Bug fix (non-breaking change that fixes an issue)
• ✨ New feature (standalone cron daemon mode)

Checklist

• I've read the Contributing Guide
• My commit messages follow Conventional Commits
• I searched for existing PRs to make sure this isn't a duplicate
• My PR contains only changes related to this fix
• I've tested on my platform: Android/Termux

[liuhao1024]

Scope concern — two unrelated features in one PR

The diff contains two separate features that should be separate PRs:

1. Cron daemon mode (hermes_cli/cron.py): Adds cron_daemon() with signal handling, event-based stop, and hermes cron daemon subcommand. Clean and focused.

2. Provider configure-without-switching (hermes_cli/main.py): Adds a 179-line _configure_provider_only() function and a "Make this your default provider? [Y/n]" prompt to hermes model. This is a UX change to the model selection flow, unrelated to cron.

Bundling unrelated changes makes review harder and increases the chance of one feature blocking the other. Consider splitting the provider config changes into a separate PR.

Also a minor note: import signal at the module level (line 5) is shadowed by import signal inside cron_daemon() (line 337). The inner import is redundant.

[alaamohanad169-ship-it]

Closing in favor of clean PR #41363 which only contains the cron daemon changes without the unrelated model wizard changes.