feat: add align_panel_columns to align Rich help panel columns

[spacemonkeyrocks]

Summary

Add an opt-in align_panel_columns: bool = False option to typer.Typer.

When disabled (the default), behaviour is unchanged: each Rich --help
options panel sizes its own columns independently. When enabled, every panel
is rendered with a shared set of fixed column widths computed from all
options in the command, so the option columns line up across panels.

Motivation

Typer renders each options panel as its own Rich Table with no fixed
column widths, so columns drift out of alignment between panels. For a
command with several rich_help_panel groups the result is ragged. The two
examples below are the real --help output of a CLI with five option panels,
at 70 columns.

Off (align_panel_columns=False):

╭─ Options ──────────────────────────────────────────────────────────╮
│ --help  -h        Show this message and exit.                      │
╰────────────────────────────────────────────────────────────────────╯
╭─ Selection options ────────────────────────────────────────────────╮
│ --config  -c      <path>  YAML config file                         │
│ --pairs   -p      <str>   Comma-separated pairs (overrides config) │
│ --years   -Y      <str>   Year range, e.g. 2017-, 2017-2025,       │
│                           2017,2020 (overrides config)             │
╰────────────────────────────────────────────────────────────────────╯
╭─ Output options ───────────────────────────────────────────────────╮
│ --human         -H             Print a table instead of JSON       │
│ --decimal       -D      <int>  Close-price decimals in --human     │
│                                mode                                │
│ --pretty-print  -P             Pretty-print the JSON output        │
╰────────────────────────────────────────────────────────────────────╯
╭─ Logging options ──────────────────────────────────────────────────╮
│              -v      <int>  Verbosity: -v info, -vv debug, -vvv    │
│ --log-path           <str>  Log file or directory (overrides       │
│ --log-level          <str>  Log level: trace, debug, info,         │
╰────────────────────────────────────────────────────────────────────╯

On (align_panel_columns=True):

╭─ Options ──────────────────────────────────────────────────────────╮
│ --help          -h              Show this message and exit.        │
╰────────────────────────────────────────────────────────────────────╯
╭─ Selection options ────────────────────────────────────────────────╮
│ --config        -c      <path>  YAML config file                   │
│ --pairs         -p      <str>   Comma-separated pairs (overrides   │
│ --years         -Y      <str>   Year range, e.g. 2017-, 2017-2025, │
╰────────────────────────────────────────────────────────────────────╯
╭─ Output options ───────────────────────────────────────────────────╮
│ --human         -H              Print a table instead of JSON      │
│ --decimal       -D      <int>   Close-price decimals in --human    │
│ --pretty-print  -P              Pretty-print the JSON output       │
╰────────────────────────────────────────────────────────────────────╯
╭─ Logging options ──────────────────────────────────────────────────╮
│                 -v      <int>   Verbosity: -v info, -vv debug,     │
│ --log-path              <str>   Log file or directory (overrides   │
│ --log-level             <str>   Log level: trace, debug, info,     │
╰────────────────────────────────────────────────────────────────────╯

Notice how -c, -p, -Y, -f, -H, -P and -v all start at the same
column, and the <path>/<str>/<int> metavar column lines up, once the
flag is enabled.

Implementation

The existing option-row building is reused unchanged; only the table column
setup branches on the flag. When enabled, a shared set of fixed column widths
is derived from every visible option in the command and the same widths are
applied to each panel. No renderer code is duplicated and no existing
behaviour changes unless the option is turned on.

Tests

Added test_align_panel_columns_true_aligns_columns and
test_align_panel_columns_false_is_default_unaligned to
tests/test_rich_utils.py.