fix(chain): note forward-referenced git commands; fix M6 prerequisites

- M11: keep `git reset --hard HEAD~1` (needed to trigger the protected-branch
  rejection) but flag it as a later-module, history-rewriting command (Module 12).
- Stop presenting rebase/pull --rebase as a casual step: M8 leads with the
  beginner-safe recreate-remote and footnotes pull --rebase as out-of-scope;
  M26 merge-only; M11 mentions rebase-merge only as out-of-scope awareness.
- M6: add Module 3 to prerequisites and back-reference the branch material it
  first taught (branch/switch/merge on docs).

Closes #33
Closes #34
Closes #35

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01TfzV5QvtPDz8LJS3Pu5VLT

modules/26-orchestrating-multiple-agents/README.md

@@ -190,7 +190,7 @@ The pattern is **fan-out, then fan-in through the front door, one branch at a ti
    first pass that lets you spend your scarce review attention only on PRs that already build and pass
    tests. CI reviews *all* of them in parallel for free; you review the survivors.
 3. **You merge them into `main` in a deliberate order**, not finish-order. Merge the foundational one
-   first (the agent that touched the joint), then rebase/merge the others on top so any conflict
+   first (the agent that touched the joint), then merge the others on top so any conflict
    surfaces against settled code. Each merge is a small, calm, Module-6 conflict resolution — on your
    terms, once, instead of two live agents corrupting each other in real time.
 4. **An assistive reviewer (Module 24) can take the first pass** on each PR — comment on the obvious