refactor: Route package consumers by manifest (#13591)
## Intent
Remove remaining package consumer behavior selected by contributor
provenance.
## Changes
- Select boundary-checkable scopes from authoritative package definition
paths instead of `ToolchainId`.
- Preserve package, aggregate, filter, and authoritative-directory
behavior in mixed repositories.
- Let LSP package indexing use parsed `package.json` sources as
capability evidence instead of ecosystem identity.
- Add focused Cargo exclusion and mixed-definition boundary coverage.
## Testing
- `cargo test -p turborepo-boundaries`
- `cargo test -p turbo --test boundaries`
- `cargo test -p turborepo-lsp`
- `cargo clippy -p turborepo-boundaries --all-targets -- -D warnings`
- `cargo clippy -p turborepo-lsp --all-targets -- -D warnings`
- Pre-push `format` and `check:toml` hooks
Advances TURBO-5798.
