PDX-510: keep testCase id allocation inside the allowed roots (review follow-up)

[mrdailey99]

Summary

Follow-up hardening from the adversarial review of PDX-510 (the provar_testcase_generate id allocator, merged in #217). Two findings, both in src/mcp/utils/testCaseId.ts.

Fixes

1. Path-policy containment (the substantive one). maxProjectTestCaseId walked the project subtree and read every *.testcase entry, with no allowed-path check on the files it read. A symlinked .testcase inside the project could therefore pull a root id out of a file outside the configured --allowed-paths — violating the containment allocateTestCaseId documents ("the project scan never leaves [the allowed roots]") and the CLAUDE.md path-safety rule. The reviewer demonstrated a working escape. Fix: only read real files (entry.isFile() && !entry.isSymbolicLink()), so an out-of-root symlinked .testcase is skipped. (Directory symlinks were already skipped — isDirectory() is false for them.)

2. Unsafe-integer ids. A .testcase with a numeric id beyond Number.MAX_SAFE_INTEGER (≥ ~16 digits) made max + 1 render in scientific notation, so the generator could emit a malformed id="1e+22". Fix: readRootTestCaseId ignores ids that aren't Number.isSafeInteger, falling back to the normal precedence.

Tests

Added to test/unit/mcp/testCaseId.test.ts:

• a symlinked .testcase pointing outside the allowed roots is ignored (id stays in-root) — skipped automatically on hosts/CI without symlink privileges;
• a 23-digit id is ignored when computing the project max.

Verification

yarn compile ... clean
yarn lint ...... clean
mcp-smoke ...... 60/60 PASS
unit suite ..... 1474 passing, 1 pending, 0 failing

Behavior on real projects is unchanged — normal files satisfy isFile(), and real corpus ids are small. No public-doc impact; docs/mcp.md untouched (no tool surface change).

Reviewed adversarially (no Copilot review per current session policy).

🤖 Generated with Claude Code

[github-actions]

Quality Orchestrator

🟢 LOW · 12 / 100 · Touches: utils. All changed files have mapped tests.

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🧪 Tests to Run · Running 1 of 57 tests

• unit/mcp/testCaseId.test.ts

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  unit/mcp/testCaseId.test.ts

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