fix(pipeline): say what actually failed, and guard against dead modules - #281

Two things — the second found while fixing the first, and it's the bigger one.

1. Trigger failures now carry their reason to the card

Every failing card read "Execution failed" while the real reason existed only in a log:

[create_pr] Failed for task …: git push --force failed:
fatal: 'origin' does not appear to be a git repository

create_pr, run_script and the managed-turn completion all called mark_complete with no detail, so the generic fallback was what the user saw. Each now passes one:

• create_pr keeps the error it was previously only logging and emitting as an ephemeral Tauri event — which helps only if a panel happens to be mounted.
• run_script names the step: Step 'lint' failed: exited 1, instead of leaving you to guess which of six steps it was.
• managed turn reports the CLI and exit code.

failure_message() applies the generic string only when there genuinely is no reason, and treats blank/whitespace-only detail as absent — otherwise a card could store an empty error that renders as no error.

Worth noting: that reason is visible at all only because #276 installed a logger. Before this session it was discarded outright.

2. ~1,165 lines of pipeline Rust are never compiled

While fixing the above I edited pipeline/completion.rs, added a test, and watched it not run.

completion.rs, engine.rs, events.rs, exit.rs and test_utils.rs have no mod declaration anywhere. Commit 234a992 "Split pipeline/mod.rs" created them and never wired them up — the split silently never took effect. mod.rs kept the live implementation, and duplicate copies of decide_completion and mark_complete_with_error have sat beside it ever since.

The trap is that it all reads like production code: cargo build passes, clippy passes, and editing it changes nothing at runtime. The real fix went into pipeline/mod.rs.

scripts/check-rust-modules.js now fails CI on any .rs file no mod declaration reaches:

Rust files that no `mod` declaration pulls in — these are never compiled:
  - src-tauri/src/pipeline/probe_dead.rs  (3 lines, never compiled)

The five known files sit in a documented KNOWN_DEAD allowlist so new files are still guarded. The check also fails if that list names a file that no longer exists, so it shrinks rather than rots. Directories holding no Rust (db/migrations/, which is .sql read at runtime) are skipped.

Decision needed from you, not me: delete the five, or finish the split. Declaring them as-is will not build — the symbols are duplicated. Filed as roadmap 2b.

Checks

cargo clippy -D warnings · cargo test --lib 570 (+1) · tsc · eslint · test:ipc · test:type-scale · test:rust-modules (new) · vitest 444.