fix(devcontainer): update shared image to e46904b1

[evanharmon1-ci]

Automated update of the immutable Harmon devcontainer toolchain image.

previous source	72bafab6a169214c546ba5f5e1061b6ee7ea9e2c
new source	e46904b128015bc03bc1b804826ac042e748c70e
manifest digest	sha256:0e968d0328ed1686d08acf0d28c55612d61fb9d3b5f6f9f8e54835fa232416a6
image	ghcr.io/evanharmon1/harmon-devcontainer:sha-e46904b128015bc03bc1b804826ac042e748c70e@sha256:0e968d0328ed1686d08acf0d28c55612d61fb9d3b5f6f9f8e54835fa232416a6

What changed

• The root and template thin Dockerfiles now consume the newly published image.
• The public manifest was validated for linux/amd64 and linux/arm64 before this branch was written.

Verification

task test:devcontainer:permissions and task verify passed before push.

Merging

Merging stays manual. A newer publication rewrites this one rolling branch and PR.