v0.4.1

Two reliability fixes for the bootstrap path users hit on day one — pip
entry-point detection, network fallback — plus a sharp agent-guidance
warning to stop program call '*.p?dat' from wedging the bridge, which
many existing PFC workflows would otherwise trigger.

Changed

• Bridge startup output is quieter: callback registration, TaskManager
  init, and historical-task counts now only go to bridge.log, not the
  PFC IPython console. The status banner shows URL + log path and stops.
  Ships when pfc-mcp's pin moves past itasca-mcp-bridge bc68380.
• addon.py drops the interactive upgrade prompt. PFC's pythonfile
  host has no usable stdin, so the input() prompt was effectively
  dead — it either hit the EOFError fallback or silently returned an
  empty string and skipped the upgrade. A top-of-file
  AUTO_UPGRADE = True constant replaces it: the bootstrap now installs
  or upgrades to the latest itasca-mcp-bridge on every start with zero
  interaction. Flip to False to pin the locally installed version.

Fixed

• addon.py no longer hard-codes pip's entry point to pip.main. That
  symbol exists in pip <= 9 (what PFC 6.0 ships) and was later restored
  as an internal shim, but it was absent in pip 10.0 through ~19.x -- a
  PFC interpreter carrying a pip from that range crashed with
  AttributeError instead of installing the bridge. The bootstrap now
  probes pip._internal.cli.main, pip._internal, and pip.main in
  turn, so it works regardless of which pip the embedded Python carries.
• A failed bridge install now points at pip's real error output and
  offers a manual pip install fallback, instead of surfacing only a
  bare exit code 2 that hid the underlying cause.

Documentation

• pfc_execute_code and pfc_execute_task docstrings now warn agents
  off itasca.command("program call '<file>.p?dat'"). PFC's
  command-script interpreter blocks the entire bridge for the script's
  duration — even bridge-internal calls like pfc_list_tasks time out,
  and recovery requires the user to manually stop PFC. If a user asks
  to run a .dat / .p3dat / .p2dat file, agents are instructed to
  read the file and translate each command into a itasca.command(...)
  call in Python instead, which preserves cycle-gap interleaving and
  keeps every command inspectable. Lots of existing PFC workflows are
  .p?dat scripts, so pointing an agent at one was previously a usage
  trap that made the toolchain look broken.
• The agentic bootstrap guide's Step 3 (agent-driven bridge install)
  now documents the PyPI -> Tsinghua mirror fallback, matching the
  fallback addon.py already performs. An agent installing the bridge
  for a user on a network that blocks PyPI previously had no documented
  retry path and would stall there.