bug: config show displays file values instead of resolved effective config

[ajianaz]

Description

cora config show displays values from config files only, not the actual resolved configuration that will be used at runtime. When env vars override config, the displayed values are misleading.

Example

# .cora.yaml: provider: zai, base_url: https://api.z.ai/...
# But CORA_PROVIDER=openai, CORA_BASE_URL=...litellm:4000 in env

$ cora config show
# Shows: provider: zai, base_url: https://api.z.ai/... (WRONG — these are file values)
# Actual runtime: provider: openai, base_url: http://litellm:4000 (from env vars)

Expected Behavior

cora config show should display the effective (resolved) configuration, with indicators of where each value comes from:

provider: openai [from: env CORA_PROVIDER]
  model: glm-5.1 [from: .cora.yaml]
  base_url: http://litellm:4000 [from: env CORA_BASE_URL]

[ajianaz]

Fixed by PR #210 and #211. cora config show now displays the effective resolved configuration with source annotations ([from: env CORA_PROVIDER], etc.).