refactor: remove Hardhat test infrastructure, use Forge exclusively

Delete testing/ and testing-coverage/ directories, .solcover.js,
and associated workspace packages. Update package scripts to use
forge test/coverage directly. Add forge-std dependency and
forge-lint configuration (exclude mixed-case rules, ignore
node_modules).

Author: RembrandtK

packages/issuance/.solcover.js

@@ -6,6 +6,7 @@ auto_detect_remappings = false
 remappings = [
     "@openzeppelin/=node_modules/@openzeppelin/",
     "@graphprotocol/=node_modules/@graphprotocol/",
+    "forge-std/=node_modules/forge-std/src/",
 ]
 cache_path = 'cache_forge'
 fs_permissions = [{ access = "read", path = "./" }]
@@ -17,3 +18,7 @@ evm_version = 'cancun'
 
 # Exclude test files from coverage reports
 no_match_coverage = "(^test/|/mocks/)"
+
+[lint]
+exclude_lints = ["mixed-case-function", "mixed-case-variable"]
+ignore = ["node_modules/**", "test/node_modules/**"]

packages/issuance/foundry.toml

@@ -27,8 +27,8 @@
     "clean": "rm -rf artifacts/ forge-artifacts/ cache_forge/ coverage/ cache/ types/ typechain-src/ .eslintcache",
     "compile": "hardhat compile --quiet",
     "typechain": "typechain --target ethers-v6 --out-dir typechain-src 'artifacts/contracts/**/!(*.dbg).json' && tsc -p tsconfig.typechain.json && rm -rf typechain-src && echo '{\"type\":\"commonjs\"}' > types/package.json",
-    "test": "pnpm --filter @graphprotocol/issuance-test test",
-    "test:coverage": "pnpm --filter @graphprotocol/issuance-test-coverage run test:coverage",
+    "test": "forge test",
+    "test:coverage": "forge coverage",
     "lint": "pnpm lint:ts; pnpm lint:sol; pnpm lint:forge; pnpm lint:md; pnpm lint:json",
     "lint:ts": "eslint '**/*.{js,ts,cjs,mjs,jsx,tsx}' --fix --cache; prettier -w --cache --log-level warn '**/*.{js,ts,cjs,mjs,jsx,tsx}'",
     "lint:sol": "solhint --fix --noPrompt --noPoster 'contracts/**/*.sol'; prettier -w --cache --log-level warn 'contracts/**/*.sol'",
@@ -60,6 +60,7 @@
     "dotenv": "catalog:",
     "eslint": "catalog:",
     "ethers": "catalog:",
+    "forge-std": "catalog:",
     "glob": "catalog:",
     "globals": "catalog:",
     "hardhat": "^3.1.5",