[kvlonge]

Why

Phase 3 of the Rust-hosted SQLBuild port (CHI-592), step 1: sqb argument parsing moves from Python argparse to Rust, removing the Python parser definitions.

Changes

• New argv parser and help/usage formatter in crates/sqlbuild-cli/src/argv/, driven by an embedded command table (command_table.json) that now defines every command and option.
• Post-parse normalisation ported: dbt passthrough, positional selectors, SQLBUILD_CONCURRENCY default, cursor/scope/test/janitor checks.
• Binding _native.parse_cli_arguments; parse_cli_invocation is a thin wrapper.
• Deleted parser.py, parser_arguments.py, sqlbuild_argument_parser.py and the parsing logic in parsing.py/errors.py.
• Movable Python: 125,499 → 124,254 lines.

Intentional differences (accepted, recorded on CHI-592):

• Help/usage uses the Python 3.13+ layout on every version; on 3.12 wrapping and choice quoting differ slightly.
• Help text is no longer coloured on 3.14.
• Negative-number detection follows 3.13 on all versions.
• The native extension now loads for --help/--version (~3 ms).

Verification

• 1,674-case oracle recorded from the old parser: 0 mismatches (exit code, stdout, stderr, parsed values and types) on 3.13 and 3.14, at widths 40–200, with colour, and with SQLBUILD_CONCURRENCY variants.
• Independent review: table vs old parser definitions action by action, plus 192 extra invocations: no differences.
• 1,670 CLI unit and integration tests; cargo test -p sqlbuild-cli; make check-ci; hygiene scan.