feat(cli): global flags after the subcommand (AWS-CLI style) — RFC, do not merge

[phitoduck]

Draft / RFC — not for merge. Opened on request to evaluate what the per-subcommand decorator approach actually looks like for moving --output (and friends) to after the subcommand name.

Summary

• Removes the shared options (--output, --log-level, --config-file, --user-id, --user-name, --hours-from-gmt, --policy-hash, --strong-name, --log-file, --log-headers) from the root @app.callback().
• Adds a _global_options decorator (src/lose_it/cli.py:179) that mutates a Typer command's signature to append the same set of typer.Options. The per-flag definitions live in one place (_GLOBAL_OPT_SPECS).
• Each subcommand opts in with a single @_global_options line. Subcommand bodies are unchanged — the decorator stashes everything on ctx.obj in the shape _open_loseit already expects.
• login couldn't take the decorator clean because of two name collisions:
  • Local --user-name flag → dropped; login now reads the override from ctx.obj["config_overrides"]["user_name"]. Same UX, same flag.
  • Local config_file Python var → renamed to write_config_to. CLI flag --write-config-to unchanged.

What this lets users do

$ loseit search "tortilla" -o json
$ loseit log "tortilla" --meal lunch --pick 1 --dry-run -o toon
$ loseit whoami --user-id 12345678 -o json

…instead of having -o json glued to the front of every command.

Gotcha worth knowing

from __future__ import annotations is on at the top of cli.py, so every parameter annotation arrives at the decorator as a string. Without inspect.signature(func, eval_str=True) the typer.Argument(...) metadata stays unresolved and every positional argument silently degrades into a --query-style option. Comment on the decorator calls that out.

Trade-offs vs the argv-pre-parse alternative

• ✅ Native --help listing on each subcommand — loseit search --help shows --output, --log-level, etc.
• ✅ No argv mangling. Each command parses through Typer normally.
• ❌ Every subcommand's --help is now ~3× longer (one block per global). On wide terminals it's fine; on narrow ones it wraps a lot.
• ❌ Login had to be refactored (the --user-name collision). Same flag and same UX, but the route through ctx.obj is slightly indirect.
• ❌ Global flags only work after the subcommand. loseit -o json search foo (the current style) stops working. That's the whole point, but it's a hard break for anyone relying on the old position.

Test plan

• uv run pytest — 165 passed, 5 deselected
• Manual: loseit version -o json, loseit search --help shows the new global block
• Reviewer to decide whether to ship, drop, or pursue the argv-pre-parse alternative instead