fix(client): invalidate stale navigation handlers

[kondv]

Description

Stop a navigation task from an old Client page from resuming auth setup or
starting injection after destroy/reinitialization.

The handler now captures its page and registration, checks that ownership before
each remaining pre-injection step, and is detached at destroy or initialization
start without removing listeners owned by callers. A new initialization resets
the old page's logout flag. Normal logout still runs its auth hooks and forces
reinjection on the current page; genuine initialization errors still reject.

This is a separate lifecycle follow-up, not a competing implementation of
#201893's navigation rejection handling. That PR already fixes both reproduced
context-loss crashes, including the newer-document-already-wired case. Its
current head still fails the old-logout/destroy/reinitialize continuation case.
This change adds no queue, binding-error suppression, inject_error contract,
timer polling, or initialize-failure browser cleanup.

This change invalidates remaining handler continuations; it does not cancel
auth-hook internals or an injection body that has already started. The original
navigation crash boundary remains the responsibility of #201893.

Related Issue(s)

Fixes #201941

Follow-up to merged #201653 and related to #201893. The original crash
regression evidence is recorded at
#201893 (comment).
This PR addresses the distinct stale-handler lifecycle gap. #201897 is
explicitly out of scope.

Testing Summary

Test Details

• npm run test-single -- tests/client-navigation.js: 19 passing.
  The same final file against main 064a3d5 gives 8 passing, 11 failing.
• Separate account-free Puppeteer fixtures ran the actual Client lifecycle on
  fresh offline Chromium pages: guards, genuine initialization rejection,
  normal logout, and old logout across full destroy/reinitialization all pass
  (4 passing). New-page navigation no longer inherits the old logout.
• The minimal lifecycle reproduction fails on main 064a3d5 and fix(client): prevent concurrent injection crash #201893 head
  4d1f29e; auth-hook/injection counts grow from [1,1,1] to [2,2,2].
  With this change they stay [1,1,1].
• ./node_modules/.bin/eslint src/Client.js tests/client-navigation.js: pass.
• ./node_modules/.bin/prettier --check src/Client.js tests/client-navigation.js tests/README.md: pass.
• node --check src/Client.js, node --check tests/client-navigation.js,
  and git diff --check: pass.
• No build script is defined. The default npm test requires real account
  configuration and sends messages, so it was not run. No live WhatsApp
  end-to-end testing is claimed.

Environment

• Machine OS: macOS 26.6.2

• Phone OS: Not applicable; account-free fixtures

• Library Version: 1.34.7, based on 064a3d5a5a3dce1281a6a12740b5a7051339d154

• WhatsApp Web Version: Not applicable; synthetic offline fixture modules

• Browser Type and Version: Chromium 149.0.7827.55; Puppeteer 24.38.0

• Node Version: 22.20.0

Type of Change

• Dependency change (package changes such as removals, upgrades, or additions)
• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Non-code change (documentation, README, etc.)

Checklist

• My code follows the style guidelines of this project.
• All new and existing tests pass (npm test).
• Typings (e.g. index.d.ts) have been updated if necessary (no public API/type changes).
• Usage examples (e.g. example.js) / documentation have been updated if applicable (tests/README.md).

The full-test checkbox is intentionally unchecked: only the account-free scope
above was run.