Normalize shared shell helpers in finance scripts

[id774]

Summary

• Unify usage() and check_commands() in run.sh and deploy.sh to the same shared contract used elsewhere: check_commands() inspects the command names given in "$@", exiting 127 when a command cannot be resolved and 126 when the resolved path is not executable; usage() calls check_commands awk before extracting the header block and exits 0.
• Split the finance-specific $CHARTS/$SUMMARY/$NOTIFY executable checks out of run.sh's check_commands() into a separate check_pipeline_commands(), preserving the existing status 1, error message, and pip install guidance. main() now calls load_environment, check_pipeline_commands, check_commands date, check_credential, check_environment, in that order.
• deploy.sh's main() now calls check_commands "$PYTHON" sudo install instead of a fixed internal list.
• Added doc/POLICY.md rules under 2.6 Shell Scripts stating that a shared helper name is an interface (same arguments/exit statuses/side effects/implementation), that repository-specific behavior belongs at the call site or in a differently named helper, and documenting the check_commands() / usage() contracts.
• Updated doc/VERSIONS' unreleased v1.0.2 (Release Date: TBD) entry with a bullet describing the normalized 127/126 command-check statuses.
• Updated Exit Codes and Version History (v1.1) headers in both run.sh and deploy.sh.

Validation

• POSIX shell syntax (sh -n run.sh, sh -n deploy.sh): PASS
• Shared helper identity (usage()/check_commands() match the specified common implementation in both scripts): PASS
• Help smoke tests (run.sh -h, run.sh --help, deploy.sh -h, deploy.sh --help): PASS (header shown, status 0, no pipeline/deployment body executed)
• Missing awk smoke test (controlled PATH without awk): PASS (status 127, common missing-command message, no header shown, no further processing)
• run.sh pipeline-command failure preservation (one of $CHARTS/$SUMMARY/$NOTIFY non-executable): PASS (status 1, existing Command not found message and pip install guidance preserved)
• run.sh missing date (pipeline commands present, date unresolvable): PASS (status 127, common missing-command message, pipeline checks passed first)
• deploy.sh non-executable $PYTHON: PASS (status 126, common non-executable message, no deployment side effects)
• pytest: PASS (513 passed, 2 deselected)
• ruff check .: PASS (all checks passed)
• Whitespace/diff scope check (git diff --check): PASS (no errors); changed files limited to run.sh, deploy.sh, doc/POLICY.md, doc/VERSIONS

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https://claude.ai/code/session_01VM2WVZz7NxE541SaTwt2wg

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