docs: update documentation to match current implementation

- SKILLS.md: Update roadmap phases with actual completion status
  - Phase 0-1 complete, Phase 2-5 partial, resolved design decisions
- OVERVIEW.md: Add HttpServer, Test effect, JIT to completed features
- ROADMAP.md: Add HttpServer, Process, Test effects to done list
- VISION.md: Update Phase 2-3 tables with current status
- guide/05-effects.md: Add Time, HttpServer, Test to effects table
- guide/09-stdlib.md: Add HttpServer, Time, Test effect docs
- reference/syntax.md: Fix interpolation syntax, remove unsupported literals
- testing.md: Add native Test effect documentation

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

docs/ROADMAP.md

@@ -273,10 +273,13 @@
 **Effect System:**
 - ✅ Effect declarations and handlers
 - ✅ Console effect (print, readLine, readInt)
-- ✅ File effect (read, write, exists, delete, listDir)
-- ✅ HTTP effect (get, post)
+- ✅ File effect (read, write, exists, delete, listDir, mkdir)
+- ✅ HTTP client effect (get, post, put, delete)
+- ✅ HTTP server effect (listen, accept, respond, stop)
+- ✅ Process effect (exec, env, args, cwd, exit)
 - ✅ Random effect (int, float, range, bool)
 - ✅ Time effect (now, sleep)
+- ✅ Test effect (assert, assertEqual, assertTrue, assertFalse)
 
 **Module System:**
 - ✅ Imports, exports, aliases
@@ -285,9 +288,12 @@
 - ✅ Circular dependency detection
 
 **Standard Library:**
-- ✅ String operations
-- ✅ List operations
-- ✅ JSON parsing/serialization
+- ✅ String operations (split, join, trim, contains, replace, toUpper, toLower, etc.)
+- ✅ List operations (map, filter, fold, head, tail, concat, reverse, find, etc.)
+- ✅ Option operations (map, flatMap, getOrElse, isSome, isNone)
+- ✅ Result operations (map, flatMap, getOrElse, isOk, isErr)
+- ✅ Math operations (abs, min, max, sqrt, pow, floor, ceil, round)
+- ✅ JSON parsing/serialization (parse, stringify, get, object, array)
 
 **Tooling:**
 - ✅ JIT compiler (~160x speedup, CLI: `lux compile`)