tri: the #[path] mounts of lab/actors/lanes orphan renum.rs for tri mods orphan, and two spec bodies are written twice #8628

Problem

#8601, #8614 and #8623 (tri lab receipt, tri actors, tri lanes) mounted their t27c gen-rust modules on one line each: #[path = "..."] #[allow(...)] mod x; // .... rustc reads that, but tri mods orphan (cli/tri/src/modreach.rs edges_from) takes a line that starts with #[path as an attribute alone, skips the mod on the same line, and hands the path to the next mod line, mod renum;. So cli/tri/src/renum.rs (994 lines, 26 tests) now reads as orphaned, and the "Orphaned modules" gate is red on master: cli/tri: orphaned rose 0 -> 1. The files are compiled; the reader is wrong about them.

tools/dupe_scan.py also counts two new copies: line_end in specs/tri/lab/receipt.t27 is specs/tri/test/report.t27's body, and pr_end in specs/tri/lanes/lanes.t27 is receipt.t27's object_end.

Fix

• Write each mount as the rest of the file does: the attributes on one line and mod x; // ... on the next. Pay the 3 added lines by joining the last three lines of cmd_lab and of cmd_actors, so main.rs does not grow.
• Import line_end from report.t27 into receipt.t27, metrics.t27 and lanes.t27. Make lanes.t27 pr_end call receipt.t27 object_end.

The gates that must turn green: tri mods orphan --gate, and python3 tools/dupe_scan.py for these two groups. bits and clear were already red before these PRs and are not theirs.