fix(newos4): honest size/network measurements + checkpoint and phantom-delete fixes (v4.6.160)

Applies the three 2026-11-09 patches after review, and fixes two more
navigator.onLine lies found while verifying them. Each patch was checked
against the live code first; one of its claims did not survive.

1. virtual-fs — phantom deletes and checkpoint bloat
   - deleteCheckpoint('nope') returned true and printed "Deleted checkpoint"
     for a name that did not exist: _resolvePath() validates intermediate
     segments only, so the leaf was never checked. New _requireLeaf() refuses
     a resolved path whose leaf is absent, and deleteCheckpoint uses it.
   - CHECKPOINT SIZE: checkpoint() cloned the whole root minus
     _snapshots/_sessions/.trash, so _mods (module originals) and
     .semantic_index were duplicated into EVERY checkpoint — measured
     2,101,686 bytes for a 2 MiB _mods. Both are now excluded on write and
     preserved across rollback (without the keep-list change a rollback would
     delete the live module originals). Measured after: 185 bytes.
   - Claim corrected: the patch also claimed deleteFile() reported success on
     a phantom path. It did not — live code already required
     `node && node.type === 'file'` and returned false. The guard is kept as
     defence-in-depth, and the test asserts the real behaviour rather than the
     claimed one.

2. module-fs — vfs-size reported ~2x the real size
   - It measured JSON.stringify(root).length: UTF-16 code units PLUS every
     structural character of the serialisation. A 1046-byte tree printed as
     1961; anything under ~5 KB printed as "0.00 MB".
   - Every number is now stored bytes (UTF-8 of file content): one measure()
     walk for the total, the per-file table, the top-directory table and the
     system dirs, so the rows add up to the total. The patch's arithmetic was
     still off in seven places, all fixed here: a UTF-16 fallback that
     reintroduced the bug when Blob was missing, a top-5 table that could
     never sum to the total (now top 10 + an aggregated remainder row), the
     top-dirs table dropping files stored at root (now a "/(root files)" row),
     a 2-decimal MB total that printed 0.00 for small VFS, three duplicate
     hand-rolled walks, readDir() used for dir sizes, and "1 files".

3. module-system — status/doctor no longer trust navigator.onLine
   - status printed "Network: Offline" from navigator.onLine, which an
     Android WebView reports false while fully connected.
   - doctor now awaits a real HEAD probe (AbortController, 4 s): only
     'reachable' is healthy, a throw is HIGH "Network: unreachable", a non-ok
     answer is MEDIUM and names the status (405 to HEAD is not "offline").
   - THE PATCH'S THRESHOLDS COULD NEVER FIRE: it compared localStorage bytes
     against navigator.storage.estimate().quota, which is the whole-origin
     quota (GBs, mostly Cache Storage), while localStorage has its own ~5 MB
     cap — a 4.5 MB localStorage reported "All systems healthy" against a
     2 GB quota. Now: localStorage measured as (key+value)*2 UTF-16 bytes with
     HIGH > 4 MiB / MEDIUM > 3 MiB, VFS measured in UTF-8 bytes with
     HIGH > 3 MiB and > 80% of the measured localStorage bytes. The origin
     quota appears only in one informational line and decides no severity.
   - Also removed navigator.onLine from version, bug-report and bug (a grep
     for it is now 0 in the module), and added a "Measured:" line so a clean
     report still shows what was measured.

4. terminal.js / module-servermon.js — the same lie, where the user looks
   - The status bar printed "❌ Offline" in red from navigator.onLine; on a
     WebView that is false while online. It now shows "📶 Network?" with a
     title pointing at `doctor` unless the browser claims online.
   - `net` test line now reads "Browser reports: offline (unreliable)" as a
     warning instead of a red failure — the real verdict comes from the
     probes that follow.

Verified: 40/40 node tests (3 new files: 36 + 53 + 34 assertions, each proven
red against the pre-patch code; the doctor test runs against the PATCH's
threshold logic and shows the 4.5 MB case staying silent). An independent
orchestrator probe re-derived all of it: phantom delete false, 2 MB _mods
absent from the checkpoint and preserved through rollback, vfs-size exact
bytes for ASCII/é/☃ nested trees, 4.5 MB localStorage HIGH despite a 2 GB
quota, failing probe unreachable, status never claiming Online/Offline.
Served bytes identical for core-bundle.js / main.html / module-system.js /
virtual-fs.js. Live Chromium on v4.6.160: vfs-size "85.8 KB (87880 bytes)
across 40 files", doctor "Measured: VFS 0.08 MB UTF-8 · localStorage 0.07 MB
UTF-16 in 14 keys", a stubbed failing probe reports HIGH unreachable, the
status bar reads "📶 Network?" when the browser lies, deleteCheckpoint on a
missing name returns false, and the console has 0 warnings and 0 JS errors.

0 files changed, 0 insertions, 0 deletions