[Bug]: check-prerequisites.sh --paths-only still runs branch validation, contradicting --help

从 scripts/bash/check-prerequisites.sh 和 issue 中描述的 --paths-only 流程开始，然后将其顺序与 scripts/powershell/check-prerequisites.ps1 以及 common.sh 中的 branch 检查进行比较。在非 feature branch 上使用 --paths-only 和 --json 重现；当路径变量被输出且命令无需进行 branch 验证即可成功时，即表示完成。

Bug Description

scripts/bash/check-prerequisites.sh --paths-only is documented as "no validation" / "no prerequisite validation", but the script runs check_feature_branch before the --paths-only early exit. The result: when the current branch does not match the feature-branch naming convention, --paths-only exits non-zero with a branch-format error, even though the caller asked for paths only and explicitly opted out of validation.

Source: https://github.com/github/spec-kit/blob/main/scripts/bash/check-prerequisites.sh#L81-L113

# Get feature paths and validate branch
_paths_output=$(get_feature_paths) || { ... ; exit 1; }
eval "$_paths_output"
unset _paths_output
check_feature_branch "$CURRENT_BRANCH" "$HAS_GIT" || exit 1   # ← runs even with --paths-only

# If paths-only mode, output paths and exit (support JSON + paths-only combined)
if \$PATHS_ONLY; then
    ...
    exit 0
fi

The header documentation (line 14) says: `--paths-only Only output path variables (no validation)` and `--help` (line 54) says `(no prerequisite validation)`. Branch validation is the most user-visible form of validation, so this contradicts the documented behavior.

Steps to Reproduce

1. Initialize a Spec Kit project: `specify init test-paths-only --integration claude`
2. Switch to a non-feature branch: `git checkout -b chore/some-cleanup`
3. Run paths-only: `./.specify/scripts/bash/check-prerequisites.sh --paths-only`

Expected Behavior

`--paths-only` succeeds and emits `REPO_ROOT`, `BRANCH`, `FEATURE_DIR`, etc., regardless of branch name (the caller asked for paths, not validation).

Actual Behavior

Exit 1 with branch-validation error (the message produced by `check_feature_branch` in `common.sh`), no path variables emitted.

Specify CLI Version

0.7.4.dev0

AI Agent

Claude Code

Suggested Fix

Move `check_feature_branch` after the `if $PATHS_ONLY; then ... exit 0; fi` block so `--paths-only` truly skips validation. Same source ordering already exists in `scripts/powershell/check-prerequisites.ps1` — please verify both are aligned.

Context

Surfaced while bulk-installing Spec Kit across 20 internal projects. `/speckit-tasks` and similar commands invoke `check-prerequisites.sh --paths-only --json` from non-feature chore branches and unexpectedly fail with branch-format errors despite the documented opt-out.