[HugoPhi]

Promote pload 1.2.0 to a stable release with compact Tab completion and
first-terminal activation guidance.

Completion follows the CLI parser for commands, aliases, options and fixed
choices. Local candidates include environment IDs/names, Python IDs/aliases and
versions, comma-separated source filters, repository names, cached/installed
package names, directories and TOML files. It reads local state on every request
without interpreter probes, downloads, SSH connections or registry writes.

Bash, Zsh, Fish and PowerShell adapters are emitted by pload shell-init along
with activation. Bash handles both token layouts around --option=value and
uses native filename quoting. The shell wrapper also dispatches remote
correctly. Installation now prints the commands needed to load the integration
in the current terminal instead of relying on a shell restart.

Zsh now uses a compact native candidate list, without repeated headings,
descriptions, or selection-menu styling. An empty prefix suggests primary
commands and environment IDs; aliases and names remain searchable by prefix,
while options appear only after typing -.
No additional runtime dependency is needed. Refresh the README with real macOS
screenshots of the current welcome, help, environment, Python, and completion
interfaces. Make upgrade instructions follow the latest stable package instead
of pinning an old version; link screenshots through the main branch so they
render on both GitHub and PyPI.

Validation:

• Local full suite: 180 passed, 2 skipped (Fish/PowerShell unavailable locally).
• Wheel and sdist both built, passed twine check, and installed in separate
  clean virtual environments with working pload --version and pload -h.
• Actual interactive Bash and Zsh Tab checks for environment/Python IDs,
  subcommands, equals-style arguments, escaped paths, incomplete quotes,
  compact Zsh output without duplicate labels or default option clutter.
• Persistent Bash/Zsh creation, initialization, activation and switching tests.
• Native Fish/PowerShell completion tests run when those shells are available;
  a dedicated Ubuntu CI job installs Fish and Zsh to exercise those adapters.
• Ruff and git diff --check pass.