Document the ADR-0018 implementation delta

[Ganesh-403]

Problem

ADR-0018 has a 54-requirement conformance profile, but implementation work did not have a repository-grounded baseline identifying which behavior already exists, which behavior conflicts with the accepted v1 model, and which surviving Linear issue owns every gap.

Root cause

The project plan was assembled across several related issues while the repository already contained substantial singleton-claim, delivery lifecycle, serving identity, and Project-qualified runtime machinery. Without one disposition map, later issues could duplicate that machinery or leave requirements unowned.

Solution

• Add the FAI-665 pre-implementation delta map.
• Classify all 54 PRJ/BND/RID/API/ENV/SEM/ISO/XPR/DBT requirements as Conforming, Partial, Missing, or Conflicting.
• Link current repository evidence and assign every gap to one surviving issue.
• Record the existing machinery that follow-up work must extend.
• Make the breaking cutover and prohibited compatibility layers explicit.

Tests added or updated

No executable tests are added because this issue is the planning/evidence baseline. FAI-679 owns final executable conformance evidence after implementation.

Verification performed

• Verified the map contains the exact 54 requirement IDs from the conformance specification.
• git diff --check
• task generate
• task generated:check
• Focused Go suites: deployment, deployment/sqlite, runtimehost, servingstate/sqlite, project/compiler, and project/graph.
• Vendored APIGen Go suite.

Remaining limitations

task ci was attempted, but the host exhausted /tmp quota during the parallel Go lanes and Chromium crashed in the site-browser lane after the preceding frontend suites passed. Those environmental failures are unrelated to this documentation-only change and are not represented as a successful full-CI run.

Linear: FAI-665

[Copilot]

Copilot was unable to review this pull request because the user who requested the review has reached their quota limit.