fix(wifi): repair provisioning — UI/firmware key mismatch, connect-on-save, asset cache-busting

[bring42]

Summary

WiFi provisioning via the web UI has been silently broken since the UI redesign (PR #29): both skins POSTed the SSID as wifiSsid while the firmware parses wifiSSID (ArduinoJson is case-sensitive), so the SSID was dropped on every save. Worse, wifiPassword did match — re-provisioning a working device saved the new password under the old SSID and could take it fully offline. The AP-churn fixes in PR #40 then (correctly) suppressed the periodic STA retry while a client sits on the SoftAP — which also removed the accidental 30s-retry path that used to pick up freshly saved creds.

Commit 1 — provisioning fix

• Skins send the canonical wifiSSID; the firmware parser stays strict (one spelling, no alias), with a comment marking the exact key as load-bearing.
• Connect-on-save: requestWifiConnect() — the config handler flags a credential change (atomic, web task → loop task) and handleWifiMaintenance() fires one immediate disconnect()+begin() with the new creds, deliberately bypassing the AP-client suppression. This is the one scan provisioning needs.
• /api/status wifi is now the object API_V2.md documents and both skins + the mock dev server already read ({connected, ssid, rssi}); ssid is the configured one so the setup page prefills while AP-only; rssi present only when connected.
• Skin honesty/UX: the confirm/toast claimed the device restarts on save (it never did); leftover mockup SSID prefills (LUME-Studio/LUME-Workshop) removed — a working save would now actually provision them; the console SSID prefill stops once the user edits the field (mobile blurs the input when the keyboard closes, so the status poll was stomping typed input).

Commit 2 — asset cache-busting (found during hardware testing)

/assets/ is served with max-age=604800 and stable filenames, so phones kept executing week-old cached JS after UI updates — the provisioning fix itself was invisible to a phone that had cached the broken app.js.

• scripts/sync_web.py stamps every asset reference with a per-file content hash (?v=<sha1[:8]>); /assets/ keeps its week-long max-age.
• HTML entry points are served Cache-Control: no-cache so a cached page can never pin an old asset set (.gz serving path preserved).

Test plan

• C3 build clean, native tests 65/65, both skins node --check
• Hardware-verified end-to-end on XIAO ESP32-C3: with a saved-but-unreachable SSID, AP serves the setup page; saving new creds fires Credentials changed; connecting to … immediately (phone still on the AP); after the phone left the AP the maintenance retry connected in <1s (Connected! IP: 172.20.10.2, mDNS/OTA up)
• sync output idempotent; version tag flips on a 1-byte content change
• data/ untouched per convention — release CI regenerates it via sync_web.py

🤖 Generated with Claude Code

[Copilot]

Pull request overview

Fixes a broken WiFi provisioning flow introduced by the UI redesign by aligning UI/firmware config keys, triggering an immediate STA connect attempt after saving credentials, and preventing stale cached UI assets from masking updates.

Changes:

• Update both UI skins to send/read the canonical wifiSSID key and improve provisioning UX (no fake restart messaging; avoid SSID prefill stomping user input).
• Add a loop-task-safe “connect-on-save” path (requestWifiConnect() + one-shot flag consumed in handleWifiMaintenance()), so newly saved creds are tried immediately even while a SoftAP client is connected.
• Implement asset cache-busting via per-file ?v=<sha1[:8]> stamping in scripts/sync_web.py, and serve HTML entry points with Cache-Control: no-cache to avoid pinning old assets.

Reviewed changes

Copilot reviewed 12 out of 12 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
ui-concepts/euclid-live/index.html	Remove mock SSID default; add placeholder for safer provisioning.
ui-concepts/euclid-live/app.js	Switch to wifiSSID key; update save confirmation/toast text.
ui-concepts/console-euclid-live/index.html	Remove mock SSID default; add placeholder.
ui-concepts/console-euclid-live/app.js	Use wifiSSID; prevent status polling from overwriting typed SSID; update UX strings.
src/storage.cpp	Document and enforce canonical wifiSSID JSON key parsing.
src/network/wifi.h	Add requestWifiConnect() API for loop-task reconnect triggering.
src/network/wifi.cpp	Implement atomic one-shot connect request consumed in maintenance loop.
src/network/server.cpp	Serve .html with Cache-Control: no-cache in SPA/static fallback paths.
src/api/status.cpp	Serve root HTML with no-cache; change /api/status wifi to structured object.
src/api/config.cpp	Detect WiFi credential changes and request immediate connect after successful save.
scripts/sync_web.py	Stamp asset references with content-hash ?v= tags while keeping long max-age for /assets/.
docs/TECH_DEBT.md	Mark stale-asset caching issue as resolved and document the approach.