fix(tools): recover wrong-home absolute paths from non-Claude models

[BOBER3r]

What & why

Follow-up to #34 (DeepSeek provider support). When running the pipeline on DeepSeek, the curator called glob with an absolute path built from a hallucinated home directory:

warn Tool "glob" threw: Path "/Users/boberik/agent-bober-workspace/agent-bober-ide/src" resolves outside the project root. Access denied.

The real home is /Users/bober4ik/… — the model invented boberik. Two mistakes compounded: it passed an absolute path at all (the tool contract says relative), and it guessed the home dir wrong. The sandbox correctly denied it, but the warning is non-fatal, so the agent silently continued with empty exploration results — degrading the run without failing it. Same class of "non-Claude model guesses its environment" problem as #34's host-environment injection.

Fix (three reinforcing layers)

• A — sandboxPath re-anchoring. When an absolute path lands outside the root but still contains the root's basename (agent-bober-ide), re-anchor the suffix (src) relative to the real root and retry. This never widens the sandbox: the re-anchored path is resolve(projectRoot, suffix) and is re-validated to be inside the root, so a genuinely-foreign path (/etc/passwd) and traversal (../..) still fail closed. Exported for direct unit testing.
• B — tighten tool path descriptions. The read/write/edit/glob/grep schemas said "relative to project root or absolute" — actively inviting the bug. Changed to "pass a relative path, not an absolute one" with an example.
• C — surface the real project root. Inject the absolute project root + an explicit "pass paths RELATIVE … do not construct absolute paths" note into every agent prompt that has a path-bearing tool, so models stop guessing the home dir at the source.

A makes it robust to the mistake; B + C reduce the mistake.

Verification

• npm run build ✅ · npm run lint ✅
• npm test → 1787 passed, 3 skipped, 1 failed (+14 new tests). The single failure (skill-bundles › package.json version › is 0.14.0) is a pre-existing stale assertion on main, unrelated to this PR.
• New tests: handlers.test.ts (9 sandboxPath cases incl. re-anchoring + security boundaries), environment.test.ts (project-root line + relative-path guidance gating).

🤖 Generated with Claude Code