test(docker): align Dockerfile contract tests with simplified TUI flow

[Sanjays2402]

Summary

Fixes two Tests failures observed on main (and therefore propagating to every open PR):

FAILED tests/tools/test_dockerfile_pid1_reaping.py::test_dockerfile_installs_tui_dependencies
FAILED tests/tools/test_dockerfile_pid1_reaping.py::test_dockerfile_materializes_local_tui_ink_package

Reference run: 25250051126 on 5d3be898a.

Root cause

The Dockerfile dropped the manual @hermes/ink materialisation gymnastics in favour of letting npm workspaces resolve the bundled package naturally. Two contract tests still asserted the older flow.

test_dockerfile_installs_tui_dependencies required:

assert "ui-tui/packages/hermes-ink/package-lock.json" in dockerfile_text

…but the lockfile is no longer COPY'd individually — the entire ui-tui/packages/hermes-ink/ tree is COPY'd instead (the workspace reference from ui-tui/package.json is file: so npm needs the real source, not just a manifest stub).

test_dockerfile_materializes_local_tui_ink_package required a 7-clause conjunction matching very specific rm -rf / npm install --omit=dev / --prefix node_modules/@hermes/ink / rm -rf .../react invocations that were stripped out when the workspace resolution was simplified.

Fix

Pin the contract the image has to satisfy (zombie reaping + bundled workspace package resolves) rather than the exact shell incantations the old flow used:

• TUI deps install: ui-tui/package.json + ui-tui/package-lock.json + ui-tui/packages/hermes-ink/ tree are all COPY'd, and an npm install/ci step runs in ui-tui.
• Bundled hermes-ink: the workspace package source is COPY'd (so await import('@hermes/ink') resolves at runtime).

Keeps the spirit of #15012 (zombie reaping) / #16690 (bundled workspace materialisation) without locking the Dockerfile into one specific implementation flavour.

Validation

$ pytest tests/tools/test_dockerfile_pid1_reaping.py -q
6 passed in 1.43s

Scope

• ✅ No production code change (test-only)
• ✅ All 6 dockerfile contract tests pass
• ✅ The pid1/tini contract (the actual reason the file exists) is unchanged

Out of scope

The other ~9 main-CI failures — separate focused PRs (#18972, #18974, #18977, #18979 already up; #18980 dotenv inbound; this one is the next).