[kvlonge]

Why

The sqlbuild executable was a second full copy of the sqb launcher, which roughly doubled the size of every wheel and installation.

Changes

• sqlbuild is now a small forwarder. It finds the sqb installed beside it and runs it with the same arguments and streams. On Unix it execs sqb. On Windows it waits on a child process, and only the child handles Ctrl+C and Ctrl+Break. If sqb is missing, it prints sqlbuild: cannot find sqb beside …; reinstall sqlbuild-cli and exits 1.
• The binary compiles only the launcher's hand-off module, without linking the library: 0.37 MB stripped instead of 6.4 MB.
• Forwarder integration tests run in the macOS and Windows scheduler recovery jobs. The wheel smoke step runs sqlbuild --version, checks that an unknown command exits 2, and writes a size summary.
• DuckShop: no edge case added. This changes only how the CLI is packaged; no project shape, data value or lifecycle sequence is involved.

Verification

• Forwarder tests pass locally on Linux and in CI on macOS (5/5) and Windows (5/5), including the Windows case where the build and temp directory are on different drives. Clippy, Windows clippy and fensu pass, and so does make check-ci.
• Wheel sizes in bytes, base → this change, measured by CI:

Platform	Wheel	Installed	sqlbuild
linux-x86_64	26,084,507 → 13,269,524	64,828,736 → 33,037,814	371,192
linux-aarch64	21,345,025 → 10,887,249	49,995,339 → 25,663,321	398,216
macos-x86_64	20,943,220 → 10,677,092	50,722,965 → 25,935,611	358,016
macos-arm64	19,989,622 → 10,202,714	46,476,332 → 23,863,674	377,312
windows-x86_64	22,420,132 → 11,363,307	62,852,577 → 31,928,799	254,464

• Independent review: two findings, both fixed. The tests now copy instead of hard-linking across drives, and the size summary reads the correct wheel directory.