chore: fix all build warnings and add stabilization roadmap

- Fix 3× ResultShadowed in cypher.nim, recovery.nim, shell.nim
- Remove 6× UnusedImport in test files
- Build is now clean: 0 warnings, 294 tests pass
- Add 4-week stabilization plan to PLAN.md (Sessions 9.1–9.4)

PLAN.md

@@ -123,3 +123,82 @@
 
 **BaraDB v1.0.0 е production-ready за blogs, e-commerce и small ERP системи.**
 **Всички distributed gaps са запълнени: replication, gossip transport, sharding migration, inter-module wiring.**
+
+---
+
+## 🆕 Сесия 9 — Stabilization Sprint (май 2026)
+
+> **Цел:** Да махнем всички workaround-и от `BARADB_DEFICIENCIES.md`, да почистим build-а и да подготвим почвата за типова система.
+> **Принцип:** Без нови светове — само stabilizaция на съществуващото.
+
+### Седмица 1: Deficiency Hunt + Build Cleanup
+
+| # | Задача | Оценка | Статус |
+|---|--------|--------|--------|
+| 9.1.1 | Почистване на 9-те build warnings (ResultShadowed + UnusedImport) | 1ч | 🔄 |
+| 9.1.2 | Issue #6: Aggregate column names (`count(*)` → `count(*)`, `max(id)` → `max(id)`) | 2ч | 🔄 |
+| 9.1.3 | Issue #5: GROUP BY bare columns — първи ред от групата за non-aggregated колони | 4-6ч | 🔄 |
+| 9.1.4 | Issue #7+8: Решение за async vs sync client + thread safety | 2ч | 🔄 |
+| 9.1.5 | Regression тестове за всички 10 deficiencies | 2ч | 🔄 |
+
+**Метрика:** NimForum миграционният код маха всички `DISTINCT` workaround-и за GROUP BY.
+
+---
+
+### Седмица 2: Type Safety in Execution Layer
+
+| # | Задача | Оценка | Статус |
+|---|--------|--------|--------|
+| 9.2.1 | `IRExpr` носи `expectedType` — всеки AST node знае дали е INT, FLOAT, TEXT, NULL | 4-6ч | 🔄 |
+| 9.2.2 | `evalExpr` връща discriminated union (`Value(kind: vkInt64/Float64/String/Null)`) вместо само `string` | 6-8ч | 🔄 |
+| 9.2.3 | `irAdd`/`irSub`/`irMul`/`irDiv` използват типовата информация (INT+INT → INT, INT+FLOAT → FLOAT) | 3ч | 🔄 |
+| 9.2.4 | `validateType` използва `Value.kind` вместо `parseInt`/`parseFloat` на string | 2ч | 🔄 |
+
+**Метрика:** Премахваме всички `try: parseFloat catch: return fallback` евристики от `evalExpr`.
+
+---
+
+### Седмица 3: JOIN Performance
+
+| # | Задача | Оценка | Статус |
+|---|--------|--------|--------|
+| 9.3.1 | Hash Join: `ON a.col = b.col` с hash table върху по-малката страна | 6ч | 🔄 |
+| 9.3.2 | Index Nested Loop Join: ако има B-Tree индекс на join колоната | 4ч | 🔄 |
+| 9.3.3 | Benchmark: `thread JOIN category` с 10K/100K/1M редове | 2ч | 🔄 |
+| 9.3.4 | Query planner избира между Nested Loop / Hash / Index въз основа на cardinality | 4ч | 🔄 |
+
+**Метрика:** JOIN с 100K редове е под 100ms.
+
+---
+
+### Седмица 4: Production Hardening
+
+| # | Задача | Оценка | Статус |
+|---|--------|--------|--------|
+| 9.4.1 | Property-based tests за `evalExpr` — случайни AST-та, проверка на invariant-и | 4ч | 🔄 |
+| 9.4.2 | Fuzz test за wire protocol — случайни байтове в `_requestQueue` на JS client-а | 3ч | 🔄 |
+| 9.4.3 | Thread safety audit: `execInsert`/`execUpdate`/`execDelete` с shared `ExecutionContext` | 3ч | 🔄 |
+| 9.4.4 | Final integration test: NimForum login + thread list + post create с BaraDB | 4ч | 🔄 |
+
+**Метрика:** 48 часа continuous fuzzing без crash. NimForum smoke test минава end-to-end.
+
+---
+
+### Рискове и митигации
+
+| Риск | Митигация |
+|------|-----------|
+| GROUP BY bare columns е по-сложен от очакваното | Fallback: SQLite behavior (първи ред), не PostgreSQL (грешка) |
+| Type safety рефакторингът чупи 294 теста | Правим го на отделен branch, не в `main` |
+| Hash Join изисква памет proportional на N | Добавяме `work_mem` лимит като PostgreSQL |
+
+---
+
+### Текущи метрики (преди сесия 9)
+
+| Метрика | Стойност |
+|---------|----------|
+| **Тестове** | 294 — 0 failures |
+| **Build warnings** | 9 (3× ResultShadowed + 6× UnusedImport) |
+| **BARADB_DEFICIENCIES** | 4 непоправени (#5, #6, #7, #8) |
+| **Workaround-и в NimForum** | 2 (GROUP BY → DISTINCT, aggregate positional access) |

src/barabadb/cli/shell.nim

@@ -164,10 +164,10 @@ proc processCommand*(state: var CliState, input: string): string =
   of "history", "\\history":
     if state.history.len == 0:
       return "(no history)"
-    var result = ""
+    var res = ""
     for i, h in state.history:
-      result &= "  " & $(i + 1) & ": " & h & "\n"
-    return result
+      res &= "  " & $(i + 1) & ": " & h & "\n"
+    return res
   of "verbose":
     state.verbose = not state.verbose
     return "Verbose mode: " & (if state.verbose: "ON" else: "OFF")

src/barabadb/graph/cypher.nim

@@ -212,7 +212,6 @@ proc executeCypher*(g: Graph, query: CypherQuery): CypherResult =
 
 proc toCypher*(query: string): string =
   ## Convert basic BaraQL to Cypher-like syntax for graph queries
-  var result = ""
   let upper = query.toUpper()
   if upper.startsWith("SELECT") and upper.contains("MATCH"):
     # Already Cypher-like

src/barabadb/storage/recovery.nim

@@ -136,19 +136,19 @@ proc analyze*(rec: CrashRecovery): RecoveryResult =
   return rec.result
 
 proc recover*(rec: CrashRecovery, db: LSMTree = nil): RecoveryResult =
-  let result = rec.analyze()
+  let analysis = rec.analyze()
 
-  if not result.applied:
-    return result
+  if not analysis.applied:
+    return analysis
 
   if db == nil:
-    return result
+    return analysis
 
   # REDO: apply committed entries (txnId < lastCommitted) to LSM-Tree
   var redoCount = 0
   var undoCount = 0
   for entry in rec.entries:
-    if entry.txnId < result.lastTxn:
+    if entry.txnId < analysis.lastTxn:
       # Committed — redo
       if entry.isDelete:
         db.delete(entry.key)

tests/join_tests.nim

@@ -1,13 +1,10 @@
 import std/unittest
 import std/os
 import std/strutils
-import std/times
 import std/monotimes
 import std/tables
-import barabadb/core/types
 import barabadb/query/executor as qexec
 import barabadb/query/parser
-import barabadb/query/ast
 import barabadb/storage/lsm
 
 proc execSql(ctx: qexec.ExecutionContext, sql: string): qexec.ExecResult =

tests/test_all.nim

@@ -4,8 +4,6 @@ import std/tables
 import std/strutils
 import std/os
 import std/asyncdispatch
-import std/times
-import std/random
 import std/monotimes
 import std/base64
 

tests/tla_faithfulness.nim

@@ -4,7 +4,6 @@
 
 import std/unittest
 import std/tables
-import std/sets
 import std/sequtils
 import std/strformat