Fix shell completion command coverage for hooks, workspace, and config subcommands

[Widthdom]

Summary

The generated zsh completion script appears to be behind the top-level CLI command list. cdidx --help advertises hooks, workspace, and config show, but cdidx completions zsh did not include those top-level command candidates in the generated commands=(...) list I inspected during dogfood testing.

Evidence

Runtime probes:

• cdidx --help listed hooks, workspace, config show, and other top-level commands.
• cdidx completions zsh generated a large completion script for version 1.36.3.
• The top-level zsh commands=(...) section included many commands such as index, search, recipes, audit, status, validate-config, validate, deps, impact, unused, hotspots, suggestions, languages, batch, mcp, completions, db, vacuum, report, license, and upgrade.
• The same top-level section appeared to omit hooks, workspace, and the config show command surface.

Why It Matters

Shell completion is a user-facing command contract. If generated completions omit supported commands, users and agent workflows can miss available functionality or assume commands are unsupported.

Acceptance Sketch

• Regenerate/adjust completion metadata so all top-level commands from cdidx --help are represented.
• Add tests comparing completion command coverage against the canonical command registry/help list.
• Include nested subcommands where the shell format supports them, especially config show, db schema, db prune, workspace list/status/use/current, and hooks install/uninstall/status.

[Widthdom]

Additional evidence from the follow-up dogfood pass after filing this issue:

• completions bash top-level commands="..." omitted hooks, workspace, and config / config show.
• completions fish top-level complete -c cdidx -n '__fish_use_subcommand' -a ... entries also omitted hooks, workspace, and config.
• completions powershell top-level $commands = @(...) likewise omitted hooks, workspace, and config.
• --help-flags still documents --completions <shell> but does not reveal that generated command coverage is incomplete.

This appears to be a shared completion-command registry gap rather than zsh-specific output.

[Widthdom]

Round 6 generated completions zsh again while exercising the broader terminal surface.

Observed:

• cdidx completions zsh works, but the generated script is large enough that the execution environment truncated the captured output.
• Search probes found completion-related coverage for zsh/bash/fish/powershell, but snapshot-style testing will need chunking or targeted assertions rather than relying on full raw output dumps.

This does not change the original coverage bug, but it adds a testing/diagnostic note: completion regression tests should compare command/subcommand coverage and key option snippets in a bounded way, otherwise failures become hard to inspect.

[Widthdom]

Round9 dogfooding confirmed the completion coverage gap extends beyond the commands already listed here:

• cdidx --help advertises hooks, workspace, config show, export, import, and lsp.
• Generated bash and zsh top-level command lists still omitted at least hooks, workspace, config, export, import, and lsp.
• completion --help is rejected with a useful suggestion: Did you mean: cdidx completions?
• completions --help correctly explains that output is a shell script and --json is not supported.

Suggested test addition:

• Compare top-level generated completion candidates for bash/zsh/fish/PowerShell against the canonical command registry, including nested command families such as config show, workspace, hooks, export, import, and lsp.

[Widthdom]

Round10 expanded the completion coverage evidence beyond zsh:

• completions fish generated a 228-line script for version 1.36.3.
• completions powershell generated a 51-line script.
• Both top-level command lists omitted newer commands visible in cdidx --help, including hooks, workspace, config, export, import, and lsp.
• PowerShell also uses a fallback/default flag set for unknown subcommands, so omitted top-level commands do not get precise subcommand completions.

This confirms the issue applies across fish and PowerShell, not only zsh.

[Widthdom]

Work started on branch fix-issue4311-4347.