feat: add intelligent tool routing and verification workflows

[Patel230]

Summary

Adds intelligent CLI tooling: dependency auditing, GitHub integration, intent detection, project verification, and tool health checks. Also includes terminal icon rendering fixes.

What's included

• Dependency audit (internal/tool/dependency_audit.go) — audit module dependencies for drift, duplicates, and security risk
• GitHub tools (internal/tool/github.go) — PR/issue helpers backed by the gh CLI
• Intent detection (internal/tool/intents.go) — route user requests to the right tool automatically
• Project verification (internal/tool/project_verify.go) — run verification workflows with self-fix support
• Tool health (internal/tool/tool_health.go) — probe tool availability and report status
• Approval gate + permission session methods + streaming additions in internal/engine
• CLI surface: cmd/chat_tools.go, cmd/root.go, diagnostics updates, new docs (docs/intelligent-cli.md)
• Icon rendering fixes (inherited from fix/icon-sizing)

Tests

• New unit tests for every new tool package
• Updated prompt/loader/icon tests

36 files changed, +1361/-79.