Define fire-and-forget flag semantics and implementation (#8)

Define comprehensive semantics for fire-and-forget feature flags:
- Eventual consistency with bounded propagation delay
- Version vectors for conflict resolution
- TTL-based caching with stale-while-revalidate
- Immutable audit logging with checksums
- Targeting rules and percentage rollouts

Reference implementation in ReScript:
- Core types (Types.res)
- Version vector conflict resolution (VersionVector.res)
- Flag evaluation engine (Evaluator.res)
- In-memory storage adapter (MemoryStore.res)
- Cache with adaptive TTL (Cache.res)
- Audit logging system (AuditLog.res)
- Main client API (Fireflag.res)

Co-authored-by: Claude <noreply@anthropic.com>

Author: hyperpolymath

docs/SEMANTICS.adoc

@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
 # fireflag - Development Tasks
 set shell := ["bash", "-uc"]
 set dotenv-load := true
@@ -8,22 +9,36 @@ project := "fireflag"
 default:
     @just --list --unsorted
 
-# Build
+# Build ReScript sources
 build:
-    @echo "TODO: Add build command"
+    deno run -A npm:rescript build
 
-# Test
-test:
-    @echo "TODO: Add test command"
+# Build in watch mode
+watch:
+    deno run -A npm:rescript build -w
 
-# Clean
+# Clean build artifacts
 clean:
-    @echo "TODO: Add clean command"
+    deno run -A npm:rescript clean
+    rm -rf src/**/*.res.js src/**/*.bs.js
 
-# Format
+# Format ReScript code
 fmt:
-    @echo "TODO: Add format command"
+    deno run -A npm:rescript format src/**/*.res
+
+# Type check
+check:
+    deno run -A npm:rescript build
+
+# Run tests
+test:
+    deno test --allow-read
+
+# Run example
+example:
+    deno run --allow-read src/example.js
 
-# Lint
+# Lint (placeholder for future rescript-eslint)
 lint:
-    @echo "TODO: Add lint command"
+    @echo "Lint: Type checking via rescript build"
+    deno run -A npm:rescript build

justfile

@@ -0,0 +1,22 @@
+{
+  "$schema": "https://raw.githubusercontent.com/rescript-lang/rescript-compiler/master/docs/docson/build-schema.json",
+  "name": "fireflag",
+  "version": "0.1.0",
+  "sources": [
+    {
+      "dir": "src",
+      "subdirs": true
+    }
+  ],
+  "package-specs": [
+    {
+      "module": "esmodule",
+      "in-source": true
+    }
+  ],
+  "suffix": ".res.js",
+  "bs-dependencies": [],
+  "warnings": {
+    "error": "+101"
+  }
+}