Changes

CLAUDE.md

@@ -102,13 +102,13 @@ Rust + Axum. Loads parquet into memory at startup.
 - `GET /api/pois?bounds=&categories=` — POIs by bounds (max 5000)
 - `GET /api/poi-categories` — Available POI category names
 
-Serves `frontend/dist/` as static fallback in production.
+Serves `frontend/dist/` as static fallback in production **only** when `--dist` is explicitly provided. When `--dist` is set, the server panics at startup if `index.html` is unreadable. When omitted (dev mode), static serving and OG injection are disabled.
 
 **Data representation (unified model):**
 - All features (numeric and enum): row-major flat `Vec<f32>`, NaN = null
 - Enum features: stored as f32 indices (0.0, 1.0, 2.0...) with `enum_values: FxHashMap<usize, Vec<String>>` mapping feature index → string values
 - String fields (address, postcode): interned/packed for memory efficiency
-- The server accepts the parquet path as a CLI argument (defaults to `data_sources/processed/wide.parquet`)
+- All CLI args are required (no hidden defaults). Optional services use `Option<String>`: `r5_url` (travel time disabled when None), `pocketbase_admin_email`/`password` (collection auto-creation skipped when None). Required config like `ollama_model` and `public_url` must be explicitly provided via env or CLI.
 
 ### Frontend (`frontend/`)
 
@@ -127,7 +127,7 @@ React 18 + TypeScript. deck.gl `H3HexagonLayer` over MapLibre GL. TailwindCSS. N
   - `useUrlSync` — URL state synchronization
 
 **Key patterns:**
-- URL encodes view/filters/POI categories/active tab as query params for shareable links. Only the current format is supported — no legacy parameter parsing (old `v=`, `f=`, or tab abbreviations are not handled).
+- URL encodes view/filters/POI categories/active tab as query params for shareable links. Only the current format is supported — no legacy parameter parsing (old `v=`, `f=`, or tab abbreviations are not handled). `tmode` is always serialized when travel time is active (no implicit default); parsing throws if `tmode` is missing when `dest` is present.
 - AbortControllers cancel in-flight requests on new queries (150ms debounce)
 - Zoom → H3 resolution defined in `consts.ts` `ZOOM_TO_RESOLUTION_THRESHOLDS`: `<7.5→5, <9.5→6, <10.5→8, <12→9, ≥12→10`
 - `POSTCODE_ZOOM_THRESHOLD = 15`: below 15 shows H3 hexagons, at/above 15 shows postcode polygons
@@ -271,7 +271,12 @@ Every UI element must use the correct token from this table. Do not invent new p
 
 ## Coding Preferences
 
-- **No backwards compatibility, no silent fallbacks**: Never add fallback codepaths for old data formats, legacy URL parameters, or alternate field names. Never silently swallow errors — always error loudly (return an error, panic, or at minimum log). If something is wrong, the code should fail visibly. One canonical name per field, one format per API, one way to do things.
+- **No backwards compatibility, no silent fallbacks**: Never add fallback codepaths for old data formats, legacy URL parameters, or alternate field names. Never silently swallow errors — always error loudly (return an error, panic, or at minimum log). If something is wrong, the code should fail visibly. One canonical name per field, one format per API, one way to do things. Specific patterns:
+  - Use `Option<String>` for truly optional config, never `default_value = ""` with `.is_empty()` checks
+  - Use `expect()` not `unwrap_or(0.0)` when a value is logically guaranteed to be present
+  - Return error responses on upstream failures, never silently drop results
+  - Don't add `#[serde(default)]` on `Option<T>` fields — serde already defaults them to `None`
+  - Required query params should be non-Option types so serde rejects missing params with 400 automatically
 - **Unified data models over special-casing**: Prefer storing different data types uniformly (e.g., enums as f32 indices alongside numeric features) rather than maintaining separate code paths
 - **Terse tests**: Test what matters in as few tests as possible — don't overcomplicate with excessive setup or edge cases that don't add value
 - **Extract and organize**: Group related utilities into proper modules (e.g., `utils/`, `parsing/`) rather than leaving helpers scattered
@@ -316,6 +321,7 @@ Follow these conventions in all Rust code:
 - **Fuzzy join**: Groups by postcode, uses `thefuzz.token_sort_ratio` with numeric token compatibility, greedy assignment from highest score
 - **Filter parsing is strict**: `parse_filters()` returns `Result` — malformed entries, unknown feature names, and unparseable numbers all return 400 Bad Request. No silent skipping of invalid filters.
 - **Data loading is strict**: `extract_string_col` and `lookup_enum_value` take a single column name (no fallback names). H3 precomputation panics on invalid coordinates. Required parquet columns must exist at startup.
+- **Travel time is strict**: `mode` param is required (400) when `destination` is set — no silent default to "car". R5 failures return 502 Bad Gateway, not silent omission. `r5_url` is `Option<String>` — returns 503 if travel time requested without R5 configured.
 - **Filter bounds format**: `south,west,north,east` (not standard bbox order)
 - **Server-side AABB filtering**: Both `/api/hexagons` and `/api/postcodes` filter results by bounding-box intersection with query bounds. Hexagons use `h3_cell_bounds()` (h3o returns degrees, not radians). Postcodes compute polygon AABB from vertices. See `bounds_intersect()` in `parsing/bounds.rs`.
 - **GridIndex returns slightly more than requested**: The 0.01° grid cells mean properties up to ~1km outside the viewport may be returned. The AABB filter in the route handlers catches these extras.