docs: fix references to things that do not exist

[Avicennasis]

Three unrelated accuracy problems, all found by checking the documentation against the tree.

1. The README describes a _config/ folder that does not exist

README.md:75 puts _config/ in the canonical workspace layout and README.md:82 calls it a Layer 3 location.

$ find . -type d -name '_config' | wc -l
0

The real Layer 3 config folders are brand-vault/ (script-to-animation, voice-driven-animation) and design-system/ (course-deck-production), which is what _core/CONVENTIONS.md:25 already says correctly. The README is the file that disagrees.

2. conventions-reference.md skips Pattern 8

The file enumerates Patterns 1-7 and 9-15. Pattern 8 (Questionnaire Design) is absent.

This matters because stages/01-discovery loads this file as "Full file" to "know the ICM patterns", and stages/04-questionnaire-design is the stage that needs Pattern 8 most. Added in the same one-line-summary-plus-pointer style as its neighbours.

3. .gitignore has no __pycache__ rule

The repo ships 15 Python scripts across the bundled pptx, elevenlabs and whisper skills. Running any of them leaves untracked __pycache__/ directories in git status. Added __pycache__/ and *.pyc.

Verification

0 remaining _config references in the README against 3 real config dirs; Patterns 1-15 all present; and the gitignore rule tested by creating a real __pycache__ directory and confirming git status stays clean.

[Avicennasis]

Correction on merge conflicts. My PR description mentioned a single one-line conflict. Having actually merged all five locally, there are three. Recording the exact resolutions so none of this costs you time.

Recommended order: #10 -> #11 -> #12 -> #13 -> #14. Each is independently mergeable; only the later ones need a touch.

Merging	File	Conflict	Keep
#12 after #11	CLAUDE.md	#11 adds the voice-driven-animation folder-map row, #12 renames MWP to ICM on the adjacent line	both: the new row and (builds new ICM workspaces)
#12 after #10	conventions-reference.md:3	#10 fixes the path, #12 fixes the wording, same line	both: The canonical ICM conventions live at ../../../_core/CONVENTIONS.md
#13 after #10/#12	conventions-reference.md	#13 inserts the Pattern 8 entry next to lines #10 changed	both: the new Pattern 8 bullet, with ../../../_core/ on the Bundled skills line below it

All three are "keep both sides" -- no judgment needed, nothing is dropped.

Verified end state with all five applied and conflicts resolved as above: bin/validate.py from #14 reports 15/15 rules passed, exit 0.

If you would rather not deal with any of this, say the word and I will collapse all five into a single PR, or rebase them into a stack so they apply in order with no conflicts at all.