feat: enforce skip_review prohibition in forge_complete tool handler

[jflowers]

Context

PR #55 adds a prompt-level prohibition against passing skip_review: true to forge_complete. However, the tool handler at internal/tools/forge/tools.go:361-374 still accepts skip_review and skip_verification as schema parameters and passes them through to forge.Complete() with no guard.

A determined or confused agent can bypass the review gate by passing skip_review: true directly, since the prohibition is prompt-only.

Requested Change

Add code-level enforcement in the forge_complete tool handler:

1. If skip_review: true is passed, return an error explaining that review cannot be skipped
2. Alternatively, strip the parameter and log a warning

This ensures the review gate is enforced at the tool boundary, not just in the prompt.

References

• PR fix: harden forge command prompt against DCP context compression #55 review thread: prompt-only prohibition flagged by @sonupreetam
• Issue bug: /forge command review-before-complete ordering collapses under context compression #47: forge review-before-complete ordering
• File: internal/tools/forge/tools.go:361-374