Tighten manifest 25-26, add steps 27-31, relax baseline lock

[Firehed]

Follow-up to #473. Scope grew after a second scan surfaced five more M×N patterns not captured by the current manifest, and after the realisation that step-21's baseline hard-lock made new tighten rules impractical.

Tightens to steps 25 and 26

• step-25 — enumerates the nine node kinds that must gain docblock coverage; notes that if docblockForExpression becomes a one-liner it is deleted and inlined rather than kept as a wrapper.
• step-26 — names Domain\LateBindingKeyword as the sole home (drops the "or ScopeFinder::resolveClassName, whichever" hedge); adds a tests/Architecture/ test that fails if the three keyword literals appear in src/ outside the enum.

New steps 27-31 for uncaptured M×N findings

Each ships a disallowedMethodCalls tighten modelled on #478's pattern.

• step-27 — union/intersection receivers: every member-lookup site in ExpressionResolver and MemberAccessDetector picks getResolvableClassNames()[0] while SymbolResolver::getAccessibleMembers iterates. Failure: function f(A|B $x) { $x->onlyB(); } — completion offers onlyB, hover returns null. Tighten pins getResolvableClassNames() to the shared helper.
• step-28 — resolveConstFetch uses one lookup, resolveFuncCall iterates NameContext::candidates. Failure: namespace App; const X = 1; echo X; — hover on X returns null. Tighten pins SymbolSource::lookupConstant to ExpressionResolver.
• step-29 — SymbolCandidates reads ->docblock + DocblockParser::extractDescription directly, bypassing HasSymbolLocation::getDocumentation(). Preventive today; a future tag-strip in getDocumentation() would silently miss completion detail. Tighten pins DocblockParser::extractDescription to HasSymbolLocation.
• step-30 — HoverHandler, SignatureHelpHandler, and CompletionItemFactory each compose format() + getDocumentation() themselves; a ResolvedSymbolPresenter consolidates the shape. Tighten pins the two methods to the presenter.
• step-31 — $this typing has an AST path in ExpressionResolver and a text-fallback side-channel in MemberAccessDetector (via a resolvedType node attribute). Deletes the attribute; routes both through one helper. Tighten pins TextFallbackHelper::resolveEnclosingClassName to that helper.

Relaxes bin/check-baseline-shrink NOW

Step-21's script failed if either baseline file existed. That made new tighten rules with residuals impossible to add. Restored the pre-step-21 shrink-only-when-present logic (comparing to origin/main). The hard "must-not-exist" lock moves to the retire step, by which point every interim tighten will have drained its residual.

Beefed-up retire (step-32)

• Restores the hard lock on bin/check-baseline-shrink.
• Adds a tests/Architecture/HandlerDependenciesRule.php that fails if any handler in src/Handler/ names ParserService, SymbolIndex, MemberResolver, or SymbolSource directly — code-enforcing the "handlers are formatters, not resolvers" invariant that CLAUDE.md documents but nothing enforces today.
• Updates CLAUDE.md Guardrails and Architecture Invariants to reflect final state: baselines permanently gone, freeze paragraph deleted, the running list of scoped disallowedMethodCalls tightens named as the seams they pin.

Considered and dropped from the scan

• Two regex classifiers for call kind (TextFallbackHelper::parseCallPattern vs CompletionClassifier) — verifier confirmed they answer different questions on the same input; no feature asymmetry possible.
• Two text regex walkers (DefaultTextSymbolExtractor vs TextFallbackHelper::findClassLikeDeclarations) — DefaultTextSymbolExtractor is a consumer of the second; already unified.

PR body written by AI, reviewed by a human.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 99.35%. Comparing base (fd82926) to head (36bfdb1).
⚠️ Report is 1 commits behind head on main.
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@            Coverage Diff            @@
##               main     #479   +/-   ##
=========================================
  Coverage     99.35%   99.35%           
  Complexity     1873     1873           
=========================================
  Files           132      132           
  Lines          4805     4805           
=========================================
  Hits           4774     4774           
  Misses           31       31           

☔ View full report in Codecov by Harness.
📢 Have feedback on the report? Share it here.

[Firehed]

Baseline expansion expected due to the nature of adding more restrictive rules.