Meters: add manual reading entry from the meter-detail Readings tab

Entering a reading by hand previously meant POST /api/v1/readings with an
API key, or a one-row CSV through the import wizard. SourceType.Manual
existed in the enum but nothing was behind it. This adds the click path,
built for the case it is actually used in: walking to each manual meter
with a phone in hand.

"Add reading" on the Readings tab opens a dialog prefilled with the
meter's last register value and the current local time, both editable:

- An on-screen keypad, because a register is read standing at the meter.
  It behaves like a calculator against the prefill - the first digit
  replaces it (a fresh register), while backspace edits it in place,
  which is the common case since only a register's last digits move.
- Typed input accepts both separators (last one wins), so a German and
  an English phone keyboard both do the right thing. ReadingEntry owns
  that rule and is unit-tested; it deliberately differs from
  GermanNumber, where a lone dot really is a thousands separator.
- A live parsed-value echo plus delta-since-last, which is the net that
  catches a mistyped digit before it is committed.
- Decrease / replaces-existing / future / backdated surfaced before
  saving, and DST spring-forward gaps refused rather than shifted.

The verdict line sits in a fixed-height, no-wrap slot above the keypad.
That is load-bearing, not cosmetic: an alert that appears there when the
value dips below the last reading moves the keys out from under the
user's thumb mid-entry, which is a guaranteed mistype on a phone. The
long-form explanation goes below the keypad, where reflow is harmless.

Saving goes through IngestionService.IngestByMeterAsync, so the
monotonic-decrease guard and inline renormalization apply exactly as for
any other ingest. A new optional quality parameter stamps the row
ReadingQuality.Manual; null preserves today's behaviour, so a source
re-reporting the same timestamp updates the value without silently
relabelling a hand-entered or imported reading.

Also: the meter-detail tabs now render times in the instance timezone
per SDD section 10, instead of raw UTC. Without it a reading entered at
18:00 reads back as 16:00. Side effect is that historic imported monthly
rows show 01:00/02:00 rather than 00:00 - correct, if noisier.

Claude-Session: https://claude.ai/code/session_01D4x3JbNKCSV4cBR9s7bJmX

CLAUDE.md

@@ -6,7 +6,7 @@ This file provides guidance to Claude Code (claude.ai/code) when working with co
 
 MeterVault is a self-hosted, local-first energy & utility metering platform: it ingests meter data from Home Assistant, Tasmota and MQTT on a schedule, stores every reading timestamped and immutable, normalizes it into consumption, and turns it into cost dashboards. Energy types (electricity, water, heating oil, gas, …) and meters are **user-defined, never hardcoded**.
 
-**Status: implemented (M0–M7) + SDD §8 panels.** The full solution is built and green — five projects, ~108 tests, working Docker deploy. `docs/SDD.md` remains the design reference; the milestone map (§12) matches the git history (M0…M7 commits). The dedicated **PV/Solar** (`/solar`), **Oil/consumable** (`/consumables`) and **meter-detail** (`/meters/{id}`) views (SDD §8.4–§8.6) are implemented as read models in `Infrastructure/Dashboard` (`SolarService`, `ConsumableService`, `MeterDetailService`) — PV meters are found by `Mode == GenerationCounter` and grid/load meters by a `role` tag in `Meter.Meta` (`MeterRoles`/`MeterMeta`), so nothing is hardcoded by name. **Admin write-CRUD** (SDD §8.7) is implemented as MudBlazor inline-dialog pages: energy types, meters (+ recompute on mode/baseline change), a meter's ingest sources (meter-detail Sources tab), tariffs, cost categories + members, and connectors (`ingestion_endpoint`, secrets by env-var reference only). `/admin/settings` is a read-only effective-config view (settings are env-driven and reproducible, not DB-stored). **Home Assistant reading** is configured here: an HA connector (`BaseUrl` + `TokenEnv`) + an HA source (entity id) drives `HomeAssistantWorker`'s REST poll, or — with the connector's **WebSocket push** toggle (`HaEndpointConfig.UseWebSocket`) — `HomeAssistantWebSocketWorker` holds a persistent `state_changed` subscription and ingests in real time (the poll worker skips WS endpoints, so each is served once; `HaWebSocketProtocol` is the pure, unit-tested handshake/parse logic). `HaConnectionTester` powers the connector "Test connection" button. **Meter topology & flow**: `MeterLink` (a directed `from→to` edge; a downstream meter is a *subsection* of an upstream one, multi-parent allowed) drives a per-energy-type page `/energy/{id}` with a hand-rolled SVG **Sankey** (`SankeyChart.razor`, since ApexCharts has no Sankey type) computed by `FlowService` (link value = downstream consumption, split proportionally across multiple parents; unaccounted remainder → an "Other" node). Upstream meters are wired cycle-safely in the meter editor; the nav lists a link per energy type. **CSV mapping wizard** (`/import/wizard`): upload an arbitrary CSV, map columns → meters/roles, dry-run preview, then commit as a revertible `import_batch` (the `/import` page lists batches with one-click revert). The `instant_rate` mode is normalized (`InstantRateNormalizer`: rate integrated over time, trapezoidal). Remaining refinement: full de-DE UI-string localization (data parsing is already de-DE) — noted at its commit. Set `MeterVault__SeedReferenceData=true` (compose: `METERVAULT_SEED=true`) for a one-command populated demo.
+**Status: implemented (M0–M7) + SDD §8 panels.** The full solution is built and green — five projects, ~108 tests, working Docker deploy. `docs/SDD.md` remains the design reference; the milestone map (§12) matches the git history (M0…M7 commits). The dedicated **PV/Solar** (`/solar`), **Oil/consumable** (`/consumables`) and **meter-detail** (`/meters/{id}`) views (SDD §8.4–§8.6) are implemented as read models in `Infrastructure/Dashboard` (`SolarService`, `ConsumableService`, `MeterDetailService`) — PV meters are found by `Mode == GenerationCounter` and grid/load meters by a `role` tag in `Meter.Meta` (`MeterRoles`/`MeterMeta`), so nothing is hardcoded by name. **Admin write-CRUD** (SDD §8.7) is implemented as MudBlazor inline-dialog pages: energy types, meters (+ recompute on mode/baseline change), a meter's ingest sources (meter-detail Sources tab), tariffs, cost categories + members, and connectors (`ingestion_endpoint`, secrets by env-var reference only). **Manual readings** are entered from the meter-detail Readings tab ("Add reading"): a touch-first dialog prefilled with the meter's last register value and the current local time, with an on-screen keypad for phone entry at the meter, a live parsed-value + delta-since-last readout, and the decrease guard surfaced before saving. It goes through `IngestionService.IngestByMeterAsync(quality: Manual)`, so it is stamped `ReadingQuality.Manual` and renormalizes inline like any other ingest — the layout of that dialog deliberately reserves fixed space for its verdict line, because anything that reflows moves the keys out from under the user's thumb mid-entry. `/admin/settings` is a read-only effective-config view (settings are env-driven and reproducible, not DB-stored). **Home Assistant reading** is configured here: an HA connector (`BaseUrl` + `TokenEnv`) + an HA source (entity id) drives `HomeAssistantWorker`'s REST poll, or — with the connector's **WebSocket push** toggle (`HaEndpointConfig.UseWebSocket`) — `HomeAssistantWebSocketWorker` holds a persistent `state_changed` subscription and ingests in real time (the poll worker skips WS endpoints, so each is served once; `HaWebSocketProtocol` is the pure, unit-tested handshake/parse logic). `HaConnectionTester` powers the connector "Test connection" button. **Meter topology & flow**: `MeterLink` (a directed `from→to` edge; a downstream meter is a *subsection* of an upstream one, multi-parent allowed) drives a per-energy-type page `/energy/{id}` with a hand-rolled SVG **Sankey** (`SankeyChart.razor`, since ApexCharts has no Sankey type) computed by `FlowService` (link value = downstream consumption, split proportionally across multiple parents; unaccounted remainder → an "Other" node). Upstream meters are wired cycle-safely in the meter editor; the nav lists a link per energy type. **CSV mapping wizard** (`/import/wizard`): upload an arbitrary CSV, map columns → meters/roles, dry-run preview, then commit as a revertible `import_batch` (the `/import` page lists batches with one-click revert). The `instant_rate` mode is normalized (`InstantRateNormalizer`: rate integrated over time, trapezoidal). Remaining refinement: full de-DE UI-string localization (data parsing is already de-DE) — noted at its commit. Set `MeterVault__SeedReferenceData=true` (compose: `METERVAULT_SEED=true`) for a one-command populated demo.
 
 ## Source of truth