fix(wiki): reduce rebuild maintenance overhead

[theyashasvipandey]

What

Reduce Wiki maintenance overhead: create candidate schema and version metadata in one transaction, report counts and revision through one revalidated read session, and sample intermediate Hub progress at most once per 100 ms. Phase transitions, completion, cancellation, and final Graph/Wiki freshness proofs remain immediate.

Why

The merged main CI run failed the small and medium Wiki rebuild timing gates. Rebuilding did redundant index/corpus inspection and persisted per-file progress updates. This removes that work without changing timing budgets, fixtures, grounding verdicts, or publication rules.

Type of change

• Bug fix
• New feature
• Refactor
• Docs
• CI/Tooling

How to test

• Added regressions cover sampled progress, cancellation during skipped updates, one-session counts/revision, concurrent canonical edits, and durable schema creation.
• Typecheck and build pass; 108 affected tests pass locally, including all five new regressions and the schema, determinism, and maintenance boundaries. One unchanged eleven-operation preview test exceeds the local Windows timeout; both full Linux test suites passed in CI.
• The same isolated medium release fixture through real Hub jobs improved local median elapsed time from 4467.5 ms to 3697.8 ms (17.2%, Windows advisory measurement). Build passes. The unchanged release-performance CI gate passes on the first measurement. Wiki rebuild p95 is 155.268 ms (small, limit 181 ms), 198.033 ms (medium, limit 301 ms), and 300.919 ms (large, limit 617 ms). Budgets and confirmation rules are untouched.

Checklist

• Tests pass (npm test)
• No breaking changes (or documented below)
• Tested locally with a real project

Code-graph changes

• This PR targets main
• A linked issue agrees on the bounded extractor/resolver scope
• The change follows the frozen LanguageExtractor or FrameworkResolver interface
• A focused fixture and assertions for the expected node/edge shape are included
• Any new grammar WASM, extension mapping, extractor, or resolver is registered
• No graph identity, reconciliation, schema, or drift-semantics changes are included, or a core / discuss-first issue is linked above