#8526: fix(docker): copy extension package.json files before pnpm install

Fixes #5292 Fixes #6151 Fixes #6989 ## Problem Bundled extensions fail to load at runtime with "Cannot find module" errors. For example, the Matrix plugin: ``` [plugins] matrix failed to load: Cannot find module '@vector-im/matrix-bot-sdk' ``` This affects all extensions that declare external dependencies (matrix, diagnostics-otel, memory-lancedb, msteams, etc.) ## Cause The Dockerfile copies `pnpm-workspace.yaml` — which declares `extensions/*` as workspace members — but doesn't copy the extension directories before `pnpm install`: ```dockerfile COPY package.json pnpm-lock.yaml pnpm-workspace.yaml .npmrc ./ COPY ui/package.json ./ui/package.json # ✅ present at install time # ❌ extensions/ not copied yet RUN pnpm install --frozen-lockfile # skips extension deps COPY . . # source arrives too late ``` pnpm matches the `extensions/*` glob against the filesystem, finds nothing, and silently skips their dependencies. ## Fix ```dockerfile COPY extensions/ ./extensions/ ``` Copy `extensions/` before install, matching the existing pattern for `ui/`. This resolves all 31 extension workspace members and their dependencies. ## Verified Built and deployed. Before: `pnpm install` reported 2 workspace projects. After: 32. Matrix plugin loads, connects, and handles encrypted messages with no errors.