docs(fr): remove references to deleted phase-4 agent personas
Remove all references to deleted phase-4 agent personas from French
documentation, matching upcoming PR #2020 changes:
- Remove agent personas: dev/Amelia, pm/John, qa/Quinn, sm/Bob,
quick-flow-solo-dev/Barry, bmad-master
- Replace deleted agent skill invocations with equivalent workflow skills
(bmad-dev-story, bmad-qa-generate-e2e-tests, bmad-quick-dev, etc.)
- Depersonalize QA references ("Quinn" → "QA Intégré" / "Workflow QA")
- Simplify workflow invocation instructions (remove "invoke agent" pattern)
- Fix upgrade-to-v6.md SM/Scrum Master references
52e37f8185