[REFACTOR] agentwatch/cli/main.py is 2,495 lines holding 23 commands

[SakethSumanBathini]

agentwatch/cli/main.py is 2,495 lines, with 23 Typer commands and 43 top-level functions —
routing, rendering, API calls, upgrade/checkout logic, policy display, server startup, export,
compare and live watch, all in one module.

What that costs today:

• a one-line change to any command drags in the whole module's import graph in tests
• commands are hard to test in isolation, so CLI behaviour is under-covered relative to the core
  package
• two people touching the CLI in the same week will conflict

Suggested fix

Split by command family into agentwatch/cli/commands/*.py, each registering onto the existing
Typer app. The CLI surface does not change — same commands, same flags, same output, same help
text.

That "no behaviour change" property is what makes it reviewable: the acceptance test is that the
existing CLI tests pass untouched, and agentwatch --help produces byte-identical output before
and after.

Worth doing in one pass rather than incrementally, since a half-split CLI is worse than either end
state. Happy to take it, but I'd want to agree the module boundaries in this issue first rather than
discovering them in review.