fix: publish repository targets under canonical package names

[ORESoftware]

What changed

• preserve the existing one-artifact-per-declared-target fan-out contract
• treat an explicit target with dir = "." as the canonical whole-repository package
• emit that artifact under the root manifest's exact org/name, even when an older manifest calls the target package *-repository
• continue re-rooting and isolating every language/schema target
• add focused unit coverage for canonical identity, full-repository contents, deterministic artifact naming, target isolation, and pack-output exclusion

Why

The interface repositories already declare [package].name correctly and already carry a [targets.repository] rooted at .. Before this patch, zed pack/publish renamed that artifact to *-repository, so zed install org/<repository-name> could not resolve the full interface package. Canonicalizing only the explicit root target fixes the requested packages without changing target-only manifests or the established pack_all cardinality.

Compatibility

• manifests without targets still publish one root package
• target-only polyglot manifests still publish exactly their declared target packages
• manifests with [targets.repository] dir = "." publish that target as the exact root package plus all language/schema targets

Checks

• focused Rust unit tests are included in src/pack.rs
• the earlier broad e2e rewrite was removed from branch history; this PR now changes only src/pack.rs
• full repository CI is running on the current head

[ORESoftware]

Manual semantic review of final head 2303e69a:

• pack_all retains one artifact per declared target for polyglot manifests.
• only dir = "." targets have their derived package name reset to the root manifest name.
• nested-target manifest rejection remains intact.
• full-repository staging still uses the existing exclusion and deterministic archive paths.
• language target re-rooting and adapter/ecosystem derivation remain unchanged.
• focused tests cover exact artifact name, full-tree contents, output-directory exclusion, and language isolation.

Hosted Actions jobs are queued rather than reporting a code failure.

[linear-code]

DEN-1837