refactor(install): restore fresh-install flow, drop transform.sh and personas

Long-standing gaps in post-install.sh plus cleanup:

- post-install.sh:18 was `sudo pacman -S paru` on the wrong
  assumption paru had landed in [extra]. Verified: paru/paru-bin
  are AUR-only. Restored the original git-clone + makepkg
  bootstrap, added the rust buildep that archinstall does not
  pull in.
- post-install.sh never installed AUR extras — walker, elephant,
  waypaper, stasis, themes all silently skipped. Now pulls
  packages/aur.txt after moonarch-git.
- packages/official.txt: drop glab, go, npm (unused) and rustup
  (only needed for the paru build, handled imperatively now).
- packages/aur.txt: add walker-bin (was missing entirely).
- transform.sh + legacy update.sh shim removed — transform was
  never used in practice.
- Apollo persona block out of CLAUDE.md, prior DECISIONS entries
  rewritten from Apollo/Ragnar to ClaudeCode.
- README Transform section and scripts/ listing trimmed.
- lib.sh ABOUTME updated — only post-install.sh sources it now.

scripts/post-install.sh

@@ -14,8 +14,16 @@ check_pacman
 # --- Install paru (AUR Helper) ---
 
 if ! command -v paru &>/dev/null; then
+    log "Installing paru build dependencies..."
+    sudo pacman -S --needed --noconfirm base-devel rust
+
     log "Installing paru..."
-    sudo pacman -S --needed --noconfirm paru
+    PARU_TMPDIR=$(mktemp -d)
+    trap 'rm -rf "$PARU_TMPDIR"' EXIT
+    git clone https://aur.archlinux.org/paru.git "$PARU_TMPDIR/paru"
+    (cd "$PARU_TMPDIR/paru" && makepkg -si --noconfirm)
+    rm -rf "$PARU_TMPDIR"
+    trap - EXIT
 else
     log "paru already installed."
 fi
@@ -66,6 +74,17 @@ log "Installing moonarch-git package..."
 sudo pacman -Sy --noconfirm
 paru -S --needed --noconfirm moonarch-git
 
+# --- Install AUR extras (cannot be hard depends of moonarch-git) ---
+
+if [[ -f "$AUR_PACKAGES" ]]; then
+    log "Installing AUR packages from $AUR_PACKAGES..."
+    # shellcheck disable=SC2046
+    paru -S --needed --noconfirm $(read_packages "$AUR_PACKAGES")
+else
+    err "AUR package list not found: $AUR_PACKAGES"
+    exit 1
+fi
+
 # --- User-level GTK4 symlinks for libadwaita apps ---
 
 THEME_NAME="Colloid-Grey-Dark-Catppuccin"