[ci skip] Flatten module wrappers into stack roots

Remove the module "xxx" { source = "./module" } indirection layer
from all 66 service stacks. Resources are now defined directly in
each stack's main.tf instead of through a wrapper module.

- Merge module/main.tf contents into stack main.tf
- Apply variable replacements (var.tier -> local.tiers.X, renamed vars)
- Fix shared module paths (one fewer ../ at each level)
- Move extra files/dirs (factory/, chart_values, subdirs) to stack root
- Update state files to strip module.<name>. prefix
- Update CLAUDE.md to reflect flat structure

Verified: terragrunt plan shows 0 add, 0 destroy across all stacks.

stacks/excalidraw/module/project/Dockerfile

@@ -1,22 +0,0 @@
-FROM golang:1.21-alpine AS builder
-
-WORKDIR /app
-COPY go.mod ./
-COPY main.go ./
-COPY static/ ./static/
-
-RUN go build -o excalidraw-library .
-
-FROM alpine:latest
-
-RUN apk --no-cache add ca-certificates
-
-WORKDIR /app
-COPY --from=builder /app/excalidraw-library .
-
-ENV DATA_DIR=/data
-ENV PORT=8080
-
-EXPOSE 8080
-
-CMD ["./excalidraw-library"]