refactor(tasks): flatten test tasks into mise.toml

Simplifies test task structure by moving all task definitions
from separate files into main mise.toml. Fixes CI "unbound variable"
error by using environment variable instead of MISE USAGE flags.

Changes:
- Move test, test:legacy, test:sqlx tasks to mise.toml
- Remove tasks/test-all.sh, tasks/test.toml, tasks/rust.toml
- Update mise.toml includes (remove rust.toml, test.toml)
- Use POSTGRES_VERSION environment variable (set by CI)
- Remove --postgres flag from CI workflow (uses env var)

Variable handling:
- Before: usage_postgres from MISE USAGE syntax (didn't work in TOML)
- After: ${POSTGRES_VERSION:-17} from environment (works everywhere)
- CI sets: POSTGRES_VERSION=${{ matrix.postgres-version }}
- Local defaults to: 17

Structure:
mise.toml (all tasks inline)
├─ test → inline script
├─ test:legacy → tasks/test-legacy.sh
└─ test:sqlx → inline script

Benefits:
✓ All tasks visible in one file
✓ No MISE USAGE parsing issues
✓ Works with CI environment variables
✓ Simpler structure (3 files removed)
✓ No unbound variable errors

Author: tobyhede

mise.toml

@@ -7,7 +7,10 @@
 #     "./tests/mise.tls.toml",
 # ]
 [task_config]
-includes = ["tasks", "tasks/postgres.toml", "tasks/rust.toml", "tasks/test.toml"]
+includes = [
+  "tasks",
+  "tasks/postgres.toml",
+]
 
 [env]
 POSTGRES_DB = "cipherstash"
@@ -27,4 +30,76 @@ run = """
 [tasks."test"]
 description = "Run all tests (legacy SQL + SQLx Rust)"
 sources = ["src/**/*_test.sql", "tests/**/*.sql", "tests/sqlx/**/*.rs"]
-run = "{{config_root}}/tasks/test-all.sh"
+run = """
+#!/bin/bash
+set -euo pipefail
+
+POSTGRES_VERSION="${POSTGRES_VERSION:-17}"
+
+echo "=========================================="
+echo "Running Complete EQL Test Suite"
+echo "PostgreSQL Version: $POSTGRES_VERSION"
+echo "=========================================="
+echo ""
+
+# Check PostgreSQL is running
+{{config_root}}/tasks/check-postgres.sh ${POSTGRES_VERSION}
+
+# Build first
+echo "Building EQL..."
+mise run build --force
+
+# Run legacy SQL tests
+echo ""
+echo "=========================================="
+echo "1/2: Running Legacy SQL Tests"
+echo "=========================================="
+mise run test:legacy --postgres ${POSTGRES_VERSION}
+
+# Run SQLx Rust tests
+echo ""
+echo "=========================================="
+echo "2/2: Running SQLx Rust Tests"
+echo "=========================================="
+mise run test:sqlx
+
+echo ""
+echo "=========================================="
+echo "✅ ALL TESTS PASSED"
+echo "=========================================="
+echo ""
+echo "Summary:"
+echo "  ✓ Legacy SQL tests"
+echo "  ✓ SQLx Rust tests"
+echo ""
+"""
+
+[tasks."test:legacy"]
+description = "Run legacy SQL tests (inline test files)"
+sources = ["src/**/*_test.sql", "tests/*.sql"]
+run = "{{config_root}}/tasks/test-legacy.sh"
+
+[tasks."test:sqlx"]
+description = "Run SQLx tests with hybrid migration approach"
+dir = "{{config_root}}"
+env = { DATABASE_URL = "postgresql://{{get_env(name='POSTGRES_USER', default='cipherstash')}}:{{get_env(name='POSTGRES_PASSWORD', default='password')}}@{{get_env(name='POSTGRES_HOST', default='localhost')}}:{{get_env(name='POSTGRES_PORT', default='7432')}}/{{get_env(name='POSTGRES_DB', default='cipherstash')}}" }
+run = """
+# Copy built SQL to SQLx migrations (EQL install is generated, not static)
+echo "Updating SQLx migrations with built EQL..."
+cp release/cipherstash-encrypt.sql tests/sqlx/migrations/001_install_eql.sql
+
+# Run SQLx migrations and tests
+echo "Running SQLx migrations..."
+cd tests/sqlx
+sqlx migrate run
+
+echo "Running Rust tests..."
+cargo test
+"""
+
+[tasks."test:sqlx:watch"]
+description = "Run SQLx tests in watch mode (rebuild EQL on changes)"
+dir = "{{config_root}}/tests/sqlx"
+run = """
+cargo watch -x test
+"""