[feat][core] Add try_relink repair primitive

[TheP2P (thep2p)]

Adds try_relink/RelinkOutcome to LookupTable, the repair counterpart to try_link (#93). Single write-lock critical section; closes #93.

[Copilot]

Pull request overview

This PR adds a repair-oriented atomic primitive, try_relink, to the LookupTable API (with RelinkOutcome) and implements it for ArrayLookupTable using a single write-lock critical section, mirroring the existing try_link atomicity guarantees. It also adds targeted unit tests that cover all acceptance-criteria outcomes and updates re-exports / test mocks to compile with the expanded trait.

Changes:

• Add RelinkOutcome and LookupTable::try_relink (repair counterpart to try_link) to the core lookup API.
• Implement try_relink in ArrayLookupTable using a single inner.write() guard and return the evicted neighbor when replacing.
• Add unit tests covering AlreadyConsistent, Forward, Relinked (with/without eviction), and out-of-range errors.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
src/node/core_test.rs	Updates a test mock LookupTable impl to include the new try_relink method.
src/core/mod.rs	Re-exports RelinkOutcome from the core module.
src/core/lookup/mod.rs	Adds RelinkOutcome and extends the LookupTable trait with try_relink + documentation.
src/core/lookup/array_lookup_table.rs	Implements try_relink under a single write lock and logs the decision.
src/core/lookup/array_lookup_table_test.rs	Adds tests for all try_relink outcomes and bounds-check errors.

Comments suppressed due to low confidence (1)

src/core/lookup/mod.rs:134

• The try_relink docs describe the "otherwise" case as an occupant being "farther from claimant than this node is", but the implementation (and try_link docs) are based on the strictly-between comparison (existing.id() < claimant.id() for Right, > for Left). Rewording this avoids implying a distance metric that isn’t enforced.

    /// - **otherwise** (the slot is empty, or its occupant sits on the wrong side, farther from
    ///   `claimant` than this node is) — `claimant` is installed as the new entry, and
    ///   [`RelinkOutcome::Relinked`] reports whatever was evicted (`None` if the slot was empty).

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