[Amber] increase upload file size limit

[jeremyeder]

Issue Description

We currently limit to 700kb. But for example Red Hat's branding guidelines are a 1Mb pdf.
Increase to 100MB and add storage-solution agnostic disk space monitoring alerts to the system's storage solution (for example minio should be supported).

Files to Fix (optional)

No response

Fix Type

Code Formatting

Confirmation

• I understand this will create an automated PR
• The changes are low-risk and reversible
• All tests should continue to pass after fixes

[github-actions]

Amber Change Summary

The following files were modified:

 components/frontend/.env.example                               |  8 ++++----
 .../agentic-sessions/[sessionName]/workspace/upload/route.ts   | 10 +++++-----
 components/manifests/minikube/ingress.yaml                     |  1 +
 components/manifests/overlays/kind/frontend-ingress.yaml       |  2 ++
 4 files changed, 12 insertions(+), 9 deletions(-)

Next Steps:

• Review that changes match the issue description
• Verify no scope creep or unintended modifications
• A PR will be created shortly for formal review

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[github-actions]

🤖 Amber has created a pull request to address this issue: #751

The changes are ready for review. All automated checks will run on the PR.

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🔍 View AI decision process (logs available for 90 days)