chore(workspace): remove redundant nested lockfiles + workspace.yaml

Three pnpm artifacts that were either Pre-Consolidation leftovers or
unintentional drift:

  - apps/context/pnpm-lock.yaml + apps/context/pnpm-workspace.yaml
    apps/context used to be its own nested workspace declaring
    apps/* and packages/*. After consolidation only apps/context/
    apps/mobile remains, and the root pnpm-workspace.yaml already
    matches it via 'apps/*/apps/*'. The nested lockfile (242 KB)
    was a separate dependency graph drifting independently from
    the root.

  - services/mana-media/packages/client/pnpm-lock.yaml
    Anomalous lockfile in a workspace sub-package. The root
    workspace already covers services/*/packages/* — no reason
    for client/ to maintain its own resolution.

Verified after deletion:
  - pnpm install completes cleanly (~16s) and now resolves
    apps/context/apps/mobile from the root lockfile (pnpm list
    confirms the workspace registration)
  - apps/api type-check still 0 errors
  - mana-auth tests still 19/19 passing

Tracked as item #26 in docs/REFACTORING_AUDIT_2026_04.md.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

apps/context/pnpm-workspace.yaml

@@ -1,3 +0,0 @@
-packages:
-  - "apps/*"
-  - "packages/*"

services/mana-media/packages/client/pnpm-lock.yaml

@@ -1,39 +0,0 @@
-lockfileVersion: '9.0'
-
-settings:
-  autoInstallPeers: true
-  excludeLinksFromLockfile: false
-
-importers:
-
-  .:
-    devDependencies:
-      '@types/node':
-        specifier: ^22.0.0
-        version: 22.19.7
-      typescript:
-        specifier: ^5.7.0
-        version: 5.9.3
-
-packages:
-
-  '@types/node@22.19.7':
-    resolution: {integrity: sha512-MciR4AKGHWl7xwxkBa6xUGxQJ4VBOmPTF7sL+iGzuahOFaO0jHCsuEfS80pan1ef4gWId1oWOweIhrDEYLuaOw==}
-
-  typescript@5.9.3:
-    resolution: {integrity: sha512-jl1vZzPDinLr9eUt3J/t7V6FgNEw9QjvBPdysz9KfQDD41fQrC2Y4vKQdiaUpFT4bXlb1RHhLpp8wtm6M5TgSw==}
-    engines: {node: '>=14.17'}
-    hasBin: true
-
-  undici-types@6.21.0:
-    resolution: {integrity: sha512-iwDZqg0QAGrg9Rav5H4n0M64c3mkR59cJ6wQp+7C4nI0gsmExaedaYLNO44eT4AtBBwjbTiGPMlt2Md0T9H9JQ==}
-
-snapshots:
-
-  '@types/node@22.19.7':
-    dependencies:
-      undici-types: 6.21.0
-
-  typescript@5.9.3: {}
-
-  undici-types@6.21.0: {}