test: extract shared fixtures, drop knip carve-outs (#627)

* refactor(domain): consolidate canonical ordering and digest helpers (#624)

* refactor(domain): consolidate canonical ordering and digest helpers

Single owner for code-point ordering (domain/canonicalOrdering.ts)
and canonical JSON digests (domain/comparisonSemantics.ts). Delete
all local compareCodePoints/compareText/digestCanonical duplicates
and migrate every importer. No re-export shims.

* fix(ci): allow slower real browser startup

* chore(config): remove dead eslint, dedupe scripts, cacheable turbo tasks

Delete eslint.config.js (oxlint is the linter), drop lint:dead alias,
pin smol-toml, fold jscpd/scan:todos into check:pr, make test:run
cacheable, align oxlint ignores.

* fix(config): hash all test inputs for cached runs

* docs: fix architecture diagram and pretty-print tool catalog

Drop dangling REPLAY edges, add dotnet/reference/error/evaluation
nodes. Emit 2-space JSON from the catalog generator and regenerate.

* test: extract shared fixtures, drop knip carve-outs

Dedupe android/apple session tests, bundler adapter headers, and
reconstruction helpers into tests/support fixtures. Delete unused
type aliases and the knip ignoreIssues block. Lower jscpd threshold
2.7 to 2.5.

.jscpd.json

@@ -1,6 +1,6 @@
 {
-  "_comment": "Test files are intentionally NOT excluded: the gate used to report zero clones because it skipped **/*.test.ts, hiding all test-tree duplication. Current actual is ~2.6% lines across src+ and tests/, down from 3.4% when tests were included. Lower this as duplication is removed.",
-  "threshold": 2.7,
+  "_comment": "Test files are intentionally NOT excluded: the gate used to report zero clones because it skipped **/*.test.ts, hiding all test-tree duplication. Current actual is ~2.4% lines across src+ and tests/, down from 3.4% when tests were included. Lower this as duplication is removed.",
+  "threshold": 2.5,
   "reporters": ["consoleFull"],
   "ignore": [
     "node_modules/**",