chore: add pre-commit hooks, tighten ESLint, activate Sentry DSN, publish CI coverage (Phase 1)

- Install husky v9 + lint-staged: pre-commit runs eslint --fix and prettier on staged files
- Tighten ESLint base config: no-console→error, ban-ts-comment (ts-ignore banned, ts-expect-error with description allowed), reportUnusedDisableDirectives→error
- Migrate web app from deprecated `next lint` to `eslint src/` with flat config and react-hooks plugin
- Convert all 5 @ts-ignore to @ts-expect-error with descriptions, remove stale disable comments
- Add NEXT_PUBLIC_SENTRY_DSN to docker-compose.prod.yml and .env.example
- Add coverage artifact upload step to CI test job
- Pre-existing violations (102 warnings) downgraded to warn in web config for Phase 2 cleanup

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

apps/web/eslint.config.mjs

@@ -0,0 +1,30 @@
+import nextjsConfig from "@capakraken/eslint-config/nextjs";
+
+/** @type {import("eslint").Linter.FlatConfig[]} */
+export default [
+  ...nextjsConfig,
+  {
+    ignores: ["e2e/**"],
+  },
+  {
+    // Temporary overrides for pre-existing violations surfaced by switching
+    // from `next lint` to the shared eslint config. Each rule should be
+    // upgraded back to "error" as the violations are resolved:
+    //   - no-explicit-any: Phase 2 (reduce `as any` casts)
+    //   - no-unused-vars: Phase 2 (remove dead code)
+    //   - no-misused-promises: Phase 2 (fix async event handlers)
+    //   - no-unsafe-function-type: Phase 2 (replace `Function` type)
+    //   - no-unused-expressions: Phase 2
+    rules: {
+      "@typescript-eslint/no-explicit-any": "warn",
+      "@typescript-eslint/no-unused-vars": ["warn", { argsIgnorePattern: "^_" }],
+      "@typescript-eslint/no-misused-promises": "warn",
+      "@typescript-eslint/no-unsafe-function-type": "warn",
+      "@typescript-eslint/no-unused-expressions": "warn",
+      "@typescript-eslint/consistent-type-imports": ["error", {
+        fixStyle: "separate-type-imports",
+        disallowTypeAnnotations: false,
+      }],
+    },
+  },
+];