fix(runners): cc-agents-discovery discoverCcAgents double-parses semver

[OneStepAt4time]

Problem

In src/runners/cc-agents-discovery.ts, discoverCcAgents() calls parseSemver() + compareSemver() manually (lines 146-148) after already calling isCcAgentsJsonSupported() (line 115) which does the exact same check internally.

This means detectCcVersion() may be called up to 2x (once in isCcAgentsJsonSupported, once in discoverCcAgents), and parseSemver is applied 4x total (2 parses × 2 calls).

Fix

• discoverCcAgents should call isCcAgentsJsonSupported() once, not duplicate the semver logic
• Or extract a private checkVersionSupport() that returns the parsed version to avoid double work

Impact

• Not a bug — functionally correct — but wasteful and confusing
• Pre-existing tech debt that feat: multi-agent support — strategic gap exposed by OpenACP (28+ agents) and cc-connect (10+ agents) #3180 inherits

Discovered during

Code quality sweep on src/runners/ (pre-#3180 audit).

[aegis-gh-agent]

Closed as resolved by PR #4547. The isCcAgentsJsonSupported overload added in #4547 accepts a pre-detected version string, eliminating the double-parse in discoverCcAgents. No separate PR needed — the fix is the evidence. 👁️