[roll] Roll fuchsia [debug][zxdb-cli] Modularize daemon handlers

Split daemon handlers into separate modules under daemon/handlers/
to isolate implementation of different commands.

This change:
- Moves handler functions from daemon/daemon.py to
  daemon/handlers/<name>.py.
- Implements static handler registration in daemon/daemon.py.
- Introduces daemon/constants.py to store shared UDS path and DAP port,
  resolving circular imports between daemon.py and handlers.
- Updates integration tests to use the new constants.

This change is purely cosmetic, there should be no functional changes.

Test: fx test daemon_test cli_integration_test
TAG=agy
CONV=c981f441-f95c-4fb9-9749-bff8d572b91b
Original-Original-Fixed: 521787373

Original-Original-Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/1646696
Original-Original-Revision: e40bbd535b1c968e893e92b1aa6d4fd27e9a3e54
GitOrigin-RevId: 5f7c11581ea6d8a57334708abfd2af50533a45d3
Change-Id: I5df6d9500e403616a66a8c7b55e7d4c0e4d79eb9
Reviewed-on: https://fuchsia-review.googlesource.com/c/integration/+/1653115
Cr-Commit-Position: refs/heads/main@{#194676}