feat(yeti): consolidate agents secret configuration under .Values.agents

[tomchop]

Description

This PR simplifies and consolidates the Yeti Agents secret configurations exclusively under .Values.agents, and sets imagePullPolicy: Always for services tracking mutable tags (bloomcheck and agents).

Key Improvements

1. Exclusively Configure Agents Secrets under .Values.agents.*:
   • agents.yetiApiKeySecret: Secret containing the Yeti API key (key: "yeti-api").
   • agents.googleApiKeySecret: Secret containing the Google Gemini API key (key: "google-api-key").
   • Decoupled from global.yeti.apiKeySecret to eliminate dual-definition ambiguity.
2. Always Pull Policy for Mutable Tags:
   • Supported bloomcheck.image.pullPolicy in templates/bloomcheck-statefulset.yaml.
   • Defaulted bloomcheck.image.pullPolicy: Always and agents.image.pullPolicy: Always in values.yaml so updates to :latest / :dev images are always fetched on pod restart.
3. Improved Chart Validation:
   • Updated _helpers.tpl (yeti.agentsEnabled) to validate agents.yetiApiKeySecret and agents.googleApiKeySecret.
4. Version Bump:
   • charts/yeti: 2.6.0 ➔ 2.7.0 (MINOR)
   • osdfir-infrastructure: 2.12.0 ➔ 2.13.0 (MINOR)

---

Verification

• helm lint charts/yeti: PASSED (0 errors)
• helm lint charts/osdfir-infrastructure: PASSED (0 errors)
• Template validation:
  • Verified agents.yetiApiKeySecret and agents.googleApiKeySecret render properly in agents-statefulset.yaml.
  • Verified imagePullPolicy: Always renders on both bloomcheck and agents.

[wajihyassine]

LGTM