fix(rocq_library): add self -Q even when out_dir is parent of dep paths

[avrabe]

What

Two-part fix that closes the standalone-build residual flagged in PR #34
(the rules_rust migration):

1. rocq_library rule (rocq/private/rocq.bzl) — stop dropping the
   self -Q out_dir prefix whenever a dep's -Q dir lives underneath
   out_dir. coqc resolves overlapping -Q mappings by deepest-ancestor
   match per source, so a parent self--Q does not override a more
   specific dep -- the dep wins for its own files. Only skip when a dep
   already maps the exact same directory.

2. examples/rust_to_rocq — give the translated point.v a
   position-stable Rocq logical prefix Example via include_path on
   both point_compiled and point_verified (they compete for the
   same output path, so Bazel only deduplicates the conflict if the args
   match). point_proofs.v imports as From Example Require Import point, which now resolves the same nested or standalone.

Why

The actual consequence of the over-cautious rocq_library check: when
out_dir was a parent directory (typical when a target lives in the root
package, e.g. building examples/rust_to_rocq as its own root module),
no self -Q reached the coqc command line — the compiled .vo got
no logical prefix, only the source basename. That broke any From <prefix> Require Import x import of a generated .v whose target
compiled at the bin root — and so the entire standalone build of the
example module.

Verified

Nix + Bazel, locally:

• bazel test //tests:all //examples/rust_to_rocq:all (nested, root module is rules_rocq_rust) — 5/5 pass
• cd examples/rust_to_rocq && bazel test //... (standalone, root module is the example) — 2/2 pass

Closes the known residual from #34.

🤖 Generated with Claude Code