passes: implement control-flow pass (4 schemes + rotation)

FlowPass rebuilds one method per scheme picked from FlowConfig:
state-spread (dense tableswitch dispatcher), computed-switch
(sparse lookupswitch over a counter local), butterfly (branch
inversion), exception-goto (dispatcher under try with a dead
catch-all), plus opaque goto-splices inside every method and
StackMapTable recomputation afterwards. Now in standard_pipeline
(between constants and noise); --no-flow is an honest off-flag.

Acceptance is real JVM, not shapes: per-scheme verify, rotation
spread, calc-prints-45 execution, paranoid smoke on lorep-1.1.0
(131 methods rebuilt, no new failures over standard).

Two verifier rules learned the hard way are now construction
invariants: no inserted mark shares a bytecode offset with a
foreign one (nop pads), and no frameless gap follows a terminal
(dead blocks are opaque-entered and throw).

Also fixes a latent frame-emitter bug the pass exposed: wide
stack values were written as slot pairs ([Double, Top]) while
javac writes one entry ([Double]); HotSpot rejects the pair.
Stacks now collapse like locals (emit::stack_vars), with a
regression test in classfile/tests/frames.rs.

docs/architecture.md

@@ -123,6 +123,7 @@ Rename → Resources → Strings → Constants → Flow → Noise → DebugInfo
 | **готово** | IR, модель, конфиг, seed/PRNG, маппинги, анализ, keep, гейт правил, `format::parse`/`write` поверх ристретто, вывод кадров `StackMapTable` |
 | **готово** | пассы rename/resources/strings/constants/noise/debug, генератор декодера, вывод мастер-секрета в рантайме |
 | **готово** | `noxis-verify` (red-паттерны, `java -Xverify:all`, метрики), CLI (`obfuscate`/`analyze`/`patterns`) |
-| **план** | схемы пасса `flow` (кадры для них уже считаются), фикстуры и regression-тесты |
+| **готово** | пасс `flow` (4 схемы + ротация + мешанина, приёмка настоящим `java`) |
+| **план** | фикстуры и regression-тесты |
 
 Детали выбора — [`stack.md`](stack.md), план — [`../todo.md`](../todo.md).