bug: ag init --force crashes with 409 duplicate key instead of overwriting

[OneStepAt4time]

Bug Report

Discovered by: Orpheus (dogfooding — install friction test)
Priority: P2 — bad UX for users who need to reinitialize

Description

Running ag init --force on an already-initialized Aegis instance crashes with HTTP 409 (Conflict) instead of overwriting the existing configuration.

Reproduction steps

1. Run ag init (completes successfully)
2. Run ag init --force
3. Observe: 409 duplicate key error / crash

Expected behavior

--force flag should overwrite existing configuration (keys, tokens, settings) without error.

Environment

• Aegis: v0.6.7-preview.1
• Node: v22.22.1
• OS: Linux

[OneStepAt4time]

Duplicate of #3351 — same DUPLICATE_KEY_NAME crash on ag init --force. PR #3384 fixes this.