docs: gate bounded doctor implementation

[ferueda]

Summary

• make the first doctor delivery measurement and interval-feasibility only
• require an explicit recorded human decision before bounded production FTS work is authorized
• make private observer callbacks consistently best-effort while keeping load, comparison, iterator, and cleanup failures fail-closed
• remove compact certification from executable scope and leave it as a separately accepted future candidate
• make the live compiled-doctor smoke rely only on observable health, existing phase timings, RSS, database bytes, and persistent-file equality
• scope correctness gates to their owning independently reviewable slices

Why

The existing plan identified the right doctor and orphan-repair hot paths, but a formal review found four execution blockers: contradictory observer failure semantics, an implicit machine-time cutover into production work, unaccepted compact scope, and private counters that the compiled live smoke could not obtain.

This change resolves those blockers without changing runtime code. The next implementation PR is now deliberately limited to generated measurement and feasibility evidence. If the interval access shape is rejected, production doctor remains unchanged and the decision is recorded before a different design is prepared.

Impact

No CLI, schema, storage, provider, doctor, repair, or compact behavior changes. This is plan-only. It prevents an executor from treating report-only timings as authorization and avoids bundling the eventual doctor refactor, orphan paging, or compact work into one oversized PR.

The local CLI upgrade to v0.6.0 and incremental reindex performed during planning are operational laptop changes and are not part of this repository diff.

Verification

• final plan review 20260723-202431-a58bdb: pass, zero findings
• earlier follow-up plan review 20260723-202151-67b0d5: pass, zero findings
• two independent executor/delta audits confirmed the four original blockers are resolved; their wording advisories were incorporated
• scoped formatting and git diff --check passed
• commit hook typecheck passed