perf(registry): memoize component-info discoverability probe per baseUrl

[ricardo-devis-agullo]

Problem: packages/oc/src/registry/routes/component-info.ts:74 called isUrlDiscoverable(href) (undici GET to the registry's own baseUrl) on EVERY HTML info-page request, adding a full HTTP round trip to each ~info view even though the result only changes when deployment config changes.

Fix:

• packages/oc/src/registry/routes/helpers/is-url-discoverable.ts: memoize the probe promise per baseUrl in a module-level Map for process lifetime, with in-flight dedup (concurrent requests share one probe). Probe logic itself unchanged.
• packages/oc/src/registry/routes/component-info.ts: no logic change; documents that the self-probe is now cached. Fallback to //host+prefix on not-discoverable preserved.

Invalidation / escape hatch:

• Exported clearDiscoverabilityCache(url?) clears one entry or the whole cache (for tests/ops).
• OC_DISCOVERABILITY_NO_CACHE=1/true bypasses the cache and forces a fresh probe every call.

Verify:

• Extended test/unit/registry-routes-helpers-is-url-discoverable.js: same baseUrl issues ONE probe, concurrent in-flight calls dedupe to one request, different baseUrl probes again, clear(url)/clear() force re-probe, env flag forces re-probe.
• New test/unit/registry-routes-component-info-discoverability.js: repeated HTML info renders with same baseUrl issue ONE undici probe; different baseUrl probes again; re-probes after clear; //host+prefix fallback kept when not discoverable.
• Results: 16/16 targeted tests pass; full registry-routes suite 198/198 pass. tsc (TS 6.0.3) and biome check clean on touched src files.