fix(linker): restore raw similarity scoring

[tom-sapletta-com]

Ticket: ticket-031

Restores the pre-refactor linker scoring contract in one production file: raw object/text similarity remains available for relation classification, while its weighted 0.48 contribution is added exactly once to the aggregate score.

Validation on base caf6551:

• npm run build: passed
• focused AST/linker/gold tests: 27 passed, 0 failed
• full fresh suite: 333 passed, 4 failed, 1 skipped out of 338
• all seven linker regressions removed
• remaining failures: three communication regressions plus ticket-030 test fixed independently in PR test(llm): repair confidence hierarchy lookup #7
• diff check and allowed-path scope: passed
• governance: only four inherited ticket-018/ticket-019 findings

No threshold, fixture, gold expectation or generated artifact changed. Independent trusted review remains required.

[tom-sapletta-com]

Combined regression integration evidence (not merge approval): base caf6551 plus implementation commits 9c25942, bbd236f, c5db5fb, and f96c0a8 was built in a detached uncommitted worktree. npm run build passed; full npm test reported 338 tests, 337 passed, 0 failed, and 1 environment-dependent JDK skip. The combined implementation diff is 4 files, 9 insertions, 6 deletions. Required governance checks and independent review remain authoritative.