Allow periods in --profile names for versioned model profiles

Problem

Codex rejects periods in profile-v2 names before looking up the corresponding config file. This prevents natural versioned profile names such as glm-5.3, even though the lookup contract is $CODEX_HOME/<name>.config.toml and glm-5.3.config.toml is an ordinary safe filename.

Reproduction

With $CODEX_HOME/glm-5.3.config.toml present:

$ codex --profile glm-5.3 exec --json --skip-git-repo-check --ephemeral 'Reply OK'
error: invalid value 'glm-5.3' for '--profile <CONFIG_PROFILE_V2>': invalid --profile value `glm-5.3`; pass a plain name such as `work`

Observed with codex-cli 0.153.4.

Cause

ProfileV2Name::from_str in protocol/src/config_types.rs accepts only ASCII alphanumerics, _, and -:

.all(|byte| byte.is_ascii_alphanumeric() || matches!(byte, b'_' | b'-'))

The parsed value is then used by resolve_profile_v2_config_path to select <name>.config.toml. A period is not a path separator and does not by itself enable traversal.

Expected behavior

--profile glm-5.3 should load $CODEX_HOME/glm-5.3.config.toml.

Acceptance criteria

• Permit . inside a profile name.
• Continue rejecting empty names, /, \, absolute paths, .. path components, and other traversal forms.
• Add parser and config-resolution tests for glm-5.3.
• Keep existing alphanumeric, hyphen, and underscore profile names compatible.

Start in protocol/src/config_types.rs at ProfileV2Name::from_str, then follow resolve_profile_v2_config_path to understand config lookup and existing validation. Add parser and config-resolution coverage for glm-5.3 while preserving rejection of empty, absolute, separator, and traversal forms. Done means the profile loads $CODEX_HOME/glm-5.3.config.toml and existing valid names remain compatible.