Shell integration templates should understand the global -C flag

[fengmk2]

Follow-up to #2031 (global -C <dir> flag), from Codex review round 4. Two gaps in the generated shell integration under crates/vite_global_cli/src/commands/env/setup.rs:

1. The vp wrapper functions (sh, fish, nu, PowerShell) intercept env use by checking the first two arguments literally, so vp -C <dir> env use bypasses the eval path: the binary prints exports instead of applying them to the current shell session. The wrappers should skip a leading -C <dir> / -C<dir> / -C=<dir> before matching env use.

2. The generated vpr completers (zsh, fish, nu, PowerShell) translate the command line by inserting run immediately after vpr, producing vp run -C <dir> ... instead of vp -C <dir> run ..., so vpr -C <dir> <TAB> completes tasks from the wrong directory (runtime vpr -C itself works; this is completion only).

Both need template changes across four shell dialects plus snapshot coverage for the generated scripts, which is why this is split out of #2031 rather than patched inline there.

[fengmk2]

Additional detail from Codex round 6 on #2031: in a shell where VP_NODE_VERSION is already set, vp -C <dir> env use <version> falls through the wrapper to command vp, writes only the session file, and leaves the stale VP_NODE_VERSION in place, so subsequent vp commands keep using the previous runtime. The wrapper fix needs to cover this (skip leading -C tokens before matching env use).