fix(pygate): install ruff+pyright so the canary gate doesn't exit-127

[roli-lpci]

The pygate composite action installed only pygate-ci but the canary gate runs ruff + pyright, which exited 127 (command not found) and produced false lint_exit_127/typecheck_exit_127 'fail/escalated' reports. Installs the linters the gate invokes. 🤖 Generated with Claude Code

[github-actions]

PyGate Quality Gate Results

PyGate Agent Brief — run_20260607044647_dd7c9c68

Mode: canary
Status: fail
Summary: 2 deterministic finding(s) require repair.

Findings & Actions

lint_exit_127

• Action: Apply targeted ruff fixes and re-run lint deterministically.
• Scope: multi_file
• Rationale: lint failed deterministically. Address this before any inferred optimizations.

typecheck_exit_127

• Action: Resolve Pyright type errors for impacted files and re-run typecheck.
• Scope: multi_file
• Rationale: typecheck failed deterministically. Address this before any inferred optimizations.

Retry Policy

• Max attempts: 3
• Max patch lines: 150
• Abort on no improvement: 2 consecutive attempts

Escalation

• Required: True
• Reason: UNRESOLVED_DETERMINISTIC_FAILURES
• Message: Escalate with evidence packet if bounded repair loop cannot clear deterministic failures.