Fix GLM-5.2 requests failing with 400 on the developer role

[estridell]

Every cline-pass/glm-5.2 request failed before generation:

request failed with status 400:
{"error":{"message":"developer is not one of ['system', 'assistant', 'user', 'tool', 'function']", ...}}

pi sends the system prompt with the developer role for reasoning models, and the GLM upstream behind ClinePass only accepts system/assistant/user/tool/function.

Fix: set compat.supportsDeveloperRole: false on the glm-5.2 catalog entry so pi sends the system prompt as a plain system message. The flag survives the live recommended-models merge because that path spreads the static entry.

Also widened PiModel.compat from the prompt-cache-only ClinePromptCacheCompat to pi-ai's OpenAICompletionsCompat so catalog entries can carry the full compat surface, and made withClinePromptCacheCompat merge into existing entry compat instead of replacing it (no behavioral change today since glm-5.2 isn't cache-flagged, but the next entry that needs both would have silently lost one).

Verified fetchClinePassModels() returns glm-5.2 with compat.supportsDeveloperRole: false on both the static fallback and the live fetch path, and a real glm-5.2 request through pi succeeds with the flag set. npm test passes.

Other ClinePass models may need the same flag if their upstreams reject developer, but I only had a failing report for glm-5.2, so I kept this scoped.