fix(build): make npm run tauri pass the correct TAURI_CONFIG to the CLI

[vidaunited]

Summary

Fresh checkouts fail tauri dev and tauri build on macOS with tauri-build's feature-allowlist error:

The `tauri` dependency features on the `Cargo.toml` file does not match the allowlist defined under `tauri.conf.json`.

Traced the root cause by wrapping cargo in a shim that logs every env var it receives from tauri-cli 2.11.2: TAURI_CONFIG is never set for the CLI's build step, contrary to the assumption in .cargo/config.toml's comment ("the Tauri CLI sets its own fully-merged TAURI_CONFIG, which therefore wins"). That file's TAURI_CONFIG=false fallback — needed so plain cargo build/cargo test match the intentionally featureless base tauri dependency (see tools/phase-c/validate-config.mjs) — silently leaks into real CLI runs instead.

This is worse than a build-script lint: the same TAURI_CONFIG env var is also read by generate_context!() to build the config embedded in the compiled binary, so a real tauri build release would silently ship with the macOS private-API window styling disabled — no error, just wrong runtime behavior.

Fix

tools/tauri-run.mjs computes the correct macOSPrivateApi value from tauri.macos.conf.json (not hardcoded, stays correct if that value changes) and sets TAURI_CONFIG explicitly before spawning the real CLI, winning over the .cargo/config.toml fallback (cargo's [env] never overrides an already-set var). Uses Node's spawnSync rather than shell env-var syntax so it works identically on the Windows/Ubuntu Parallels CI legs, which invoke the same npm run tauri -- build --no-bundle entrypoint.

.cargo/config.toml is untouched: its false fallback still correctly serves cargo test/cargo build and phase-c's release-build step, which don't exercise generate_context!()'s runtime path.

Test plan

Verified cold (fresh clone, rm -rf target) on macOS:

• npm run tauri dev — starts and builds cleanly
• cargo test --manifest-path src-tauri/Cargo.toml --lib — 272 passed
• npm run build
• npm run build:phase-c — 6/6 passed
• PHASE_C_STRICT_TAURI=1 npm run build:phase-c — 7/7 passed, including the real tauri build --no-bundle path