Preserve the active worktree snapshot on dev for follow-on integration

The root checkout already contained a large in-progress proxy, transformer,
and settings refactor. This commit captures that exact work on a dedicated
local dev branch without disturbing the original dirty worktree, so the
changes can be continued or split from dev instead of living only as
uncommitted state.

Constraint: The source checkout was already dirty on another branch, so the move had to preserve that worktree while excluding local .idea and .omx residue from the commit
Rejected: Switch the dirty root checkout directly to dev | risked disrupting the original branch and in-progress state
Confidence: medium
Scope-risk: broad
Reversibility: clean
Directive: Treat this as a transfer snapshot; fix the failing oauth/accountTokens/normalized/docs test regressions before merge or publication
Tested: git diff --check; npm run typecheck; npm run repo:drift-check
Not-tested: Clean test pass; npm test currently fails in oauth routes, accountTokens sync, shared normalized helpers, gemini route expectations, architecture-boundaries, and docs vitepress config

docker/Dockerfile

@@ -1,4 +1,3 @@
-# syntax=docker/dockerfile:1.7
 # Keep the Docker base on Node 22 because the official Node 24/25 slim images
 # no longer publish linux/arm/v7 manifests, which breaks our armv7 Docker jobs.
 FROM node:22-bookworm-slim AS builder
@@ -12,12 +11,12 @@ RUN apt-get update \
 ENV PYTHON=/usr/bin/python3
 
 COPY package.json package-lock.json ./
-RUN --mount=type=cache,target=/root/.npm npm ci --ignore-scripts --no-audit --no-fund
+RUN npm ci --ignore-scripts --no-audit --no-fund
 RUN npm rebuild esbuild sharp better-sqlite3 --no-audit --no-fund
 
 COPY . .
 RUN npm run build:web && npm run build:server
-RUN --mount=type=cache,target=/root/.npm npm prune --omit=dev --no-audit --no-fund
+RUN npm prune --omit=dev --no-audit --no-fund
 
 FROM node:22-bookworm-slim