Trim PARS vignette prose — drop implementation details

Co-Authored-By: Claude Opus 4.6 <[email protected]>

Author: NewGraphEnvironment

vignettes/pars-floodplain.Rmd

@@ -133,12 +133,7 @@ see the
 
 The vignette renders against pre-computed outputs from
 `data-raw/wsg_vignette_data.R` so it builds fast and doesn't touch the
-network or database. The hydro / context layers ship as a single
-multi-layer GeoPackage and the rasters as separate GeoTIFFs (raster
-tiles in GPKG would lose the continuous DTM precision and the binary
-valleys semantics — wrong format for analytical layers).
-
-Direct downloads of the cached Parsnip River Watershed Group bundle from the repo (open in QGIS
+network or database. Direct downloads of the cached Parsnip River Watershed Group bundle from the repo (open in QGIS
 or any GDAL-aware tool):
 
 - [`pars.gpkg`](https://github.com/NewGraphEnvironment/flooded/raw/main/inst/vignette-data/pars.gpkg)
@@ -200,54 +195,10 @@ elsewhere. `flooded::fl_dem_aoi()` reads it via `/vsicurl/`, so the only
 bytes transferred are those intersecting the AOI — bandwidth scales
 with the AOI, not with the COG size.
 
-The DEM was fetched in `data-raw/wsg_vignette_data.R` with a single
-call, passing the streams as the AOI so the crop hugs the stream
-corridor (a memory-efficient pattern for large watersheds with sparse
-stream networks):
-
-```{r dem-fetch, eval = FALSE}
-dem <- flooded::fl_dem_aoi(streams, buffer = 2000)
-```
-
-The default `source = NULL` resolves to the canonical MRDEM-30 DTM
-`/vsicurl/` URL inside `flooded::fl_dem_aoi()`. `buffer = 2000` extends
-the AOI by 2 km in metres before crop. To override the source — e.g.,
-to fetch a LidarBC COG — pass `source = "/vsicurl/https://.../tile.tif"`.
-
 ## Streams and waterbodies
 
 Streams are habitat segments modelled as accessible to bull trout from
-[bcfishpass](https://github.com/smnorris/bcfishpass) outputs. bcfishpass
-runs weekly on a hosted virtual machine and republishes the
-`streams_bt_vw` view, so the data is current to within a week of any
-upstream FWA, observation, or barrier change.
-
-```{r bcfishpass-version, echo = FALSE}
-ver <- readRDS(system.file("vignette-data/pars_meta.rds",
-                           package = "flooded", mustWork = TRUE))
-```
-
-This run is built against bcfishpass `r ver$bcfishpass_version` (LINEAR
-model, completed `r ver$bcfishpass_date`). The version stamp is cached
-at data-raw time (see `data-raw/wsg_vignette_data.R`) so the vignette
-renders without touching the database.
-
-The streams query is a single
-[`fresh::frs_db_query()`](https://newgraphenvironment.github.io/fresh/reference/frs_db_query.html)
-call — every row in `bcfishpass.streams_bt_vw` is already classified
-accessible (`access IN (1, 2)` = assessed or modelled), so filtering to
-"best accessible habitat order 3+" needs no working-table classification:
-
-```r
-streams <- fresh::frs_db_query(conn, "
-  SELECT segmented_stream_id, blue_line_key, waterbody_key,
-         upstream_area_ha, map_upstream, channel_width, stream_order,
-         gradient, mapping_code, access, spawning, rearing, geom
-  FROM bcfishpass.streams_bt_vw
-  WHERE watershed_group_code = 'PARS'
-    AND access IN (1, 2)
-    AND stream_order >= 3")
-```
+[bcfishpass](https://github.com/smnorris/bcfishpass).
 
 Waterbodies (lakes + wetlands) come from `whse_basemapping.fwa_lakes_poly`
 and `whse_basemapping.fwa_wetlands_poly` joined on `waterbody_key` — only