fix(completion): zsh completion supports aliases

[toby-griffiths]

I'd noticed that alias would not autocomplete on MacOS with zsh, so taking inspiration from it being fixed in fish, I thought I'd fix the zsh issue. I had a good search for any previous discussion on this, but didn't turn anything up, so apologies if I've missed this somewhere.

Claude & Co-Pilot did a lot of the heavy lifting here, but I've reviewed the code any believe it all to be good and proper.

The Fix

The ZSH completion script not parses the (aliases: ...) parenthetical from task --list-all output and add each alias as a separate completion entry, so typing an alias prefix and pressing Tab now completes correctly. When verbose mode is on, aliases are shown with an "alias for " description.

Tests

As this is a shell script I've not written tests, however Co-Pilot provided the following script to validate the logic, in cause it's useful, or you want this integrtaing into this PR as a test file somehow (please advise how)…

#!/bin/zsh

# Simulate task output
output="task: Available tasks for this project:
* build:            Build the project	(aliases: b, compile)
* deploy:           Deploy to production	(aliases: d, push)
* test:             Run tests	(aliases: t, check)"

echo "Testing alias completion regex patterns...\n"

# Test cases
test_items=(
    "build:            Build the project	(aliases: b, compile)"
    "deploy:           Deploy to production	(aliases: d, push)"
    "test:             Run tests	(aliases: t, check)"
    "single:           Single alias task	(aliases: s)"
    "nospace:          No space after comma	(aliases: foo,bar,baz)"
)

for item in "${test_items[@]}"; do
    echo "Testing: $item"

    if [[ "$item" =~ '\(aliases: ([^)]+)\)' ]]; then
        echo "  ✓ Regex matched"
        local aliases_str="${match[1]}"
        echo "  Captured aliases string: '$aliases_str'"

        # Test splitting
        local -a alias_names
        alias_names=("${(@s:, :)aliases_str}")
        echo "  Split into ${#alias_names[@]} alias(es):"

        for alias_name in "${alias_names[@]}"; do
            # Trim whitespace
            alias_name="${alias_name## }"
            alias_name="${alias_name%% }"

            if [[ -z "$alias_name" ]]; then
                echo "    - (empty - skipped)"
            else
                echo "    - '$alias_name'"
            fi
        done
    else
        echo "  ✗ Regex did not match"
    fi
    echo ""
done

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