docs(build): document real-data workflows

Clarify that `just build` is the production no-bundle launcher build, while
fixture builds are explicit. Document package-directory generation, the
`LANSPREAD_GAMES_DIR` and `--set GAMES_DIR` default-run forms, the metadata
cache behavior, and the force-refresh override so the catalogue workflow is
usable without consulting the recipe implementation.

Test Plan:
- `prettier --check --prose-wrap always --print-width 80 README.md CLAUDE.md` -- passed
- `just --fmt --check` -- passed
- `git diff --cached --check` -- passed

CLAUDE.md

@@ -27,8 +27,14 @@ Top-level `Cargo.toml` pins workspace dependency versions; per-crate
 
 Never use normal cargo ... commands, use the just ... commands instead.
 
-- `just run` — run the GUI in dev mode.
+- `just run` — run the fixture GUI, or real data when `LANSPREAD_GAMES_DIR` is
-- `just build` — build the GUI without bundling (also dev mode).
+  set.
+- `just build` — validate production authority and build the launcher without
+  bundling.
+- `just build-production PACKAGES_DIR` — generate/reuse production authority and
+  build.
+- `just run-fixture` / `just build-fixture` — use the test-only catalogue
+  explicitly.
 - `just fmt` — format the workspace.
 - `just clippy` — lint the workspace.
 - `just test` — run the workspace unit tests.

README.md

@@ -31,18 +31,43 @@ builds.
 
 ## Daily development
 
-Run the desktop app with the checked-in development catalog:
+Run the desktop app with the checked-in test catalog:
 
 ```bash
 just run
 ```
 
-Build without bundling:
+Build a launcher from the already-published production catalog without creating
+an installer:
 
 ```bash
 just build
 ```
 
+Generate the production catalog from a package tree when necessary, then build
+the same no-bundle launcher:
+
+```bash
+just build-production /srv/lanspread/packages
+```
+
+To make the default `just` command use a real package tree, set the directory
+before invoking it. The command generates or reuses the production catalog and
+then runs the launcher with the production resource map:
+
+```bash
+LANSPREAD_GAMES_DIR=/srv/lanspread/packages just
+# Equivalent Just-variable form:
+just --set GAMES_DIR /srv/lanspread/packages
+```
+
+The fixture-only paths remain explicit:
+
+```bash
+just run-fixture
+just build-fixture
+```
+
 Run the standard checks before committing:
 
 ```bash
@@ -52,9 +77,10 @@ just test
 just frontend-test
 ```
 
-`just run` and `just build` first check the default development catalog. The
+`just run` uses the fixture path only when `LANSPREAD_GAMES_DIR` is unset.
-workspace Rust commands explicitly opt into that exact fixture resource map so
+`just build` always uses the production resource map and production profile; use
-Tauri's build script does not mistake test data for production authority.
+`just build-fixture` when a fixture build is intended. Tauri's build script
+still rejects fixture resources unless the explicit fixture opt-in is present.
 
 ## Catalog checksums and production manifests
 
@@ -111,6 +137,18 @@ Generate the complete production manifest set:
 just catalog-generate-production /srv/lanspread/packages
 ```
 
+The `--all` recipe keeps a local metadata-only stamp in
+`.lanspread/catalog-cache/production.json`. It compares the package tree's
+paths, entry types, sizes, and nanosecond mtimes, plus the catalog database and
+`unrar` metadata. If those values and the published output still match, the
+expensive package hashing and extraction step is skipped. This is only a
+performance cache: `catalog-check-production` and every production build still
+validate the catalog authority. Force a refresh when needed:
+
+```bash
+LANSPREAD_CATALOG_FORCE=1 just catalog-generate-production /srv/lanspread/packages
+```
+
 The publisher first checks every selected package's `version.ini` against
 `game.db`, then independently reads and hashes each selected package twice
 before publication. Under a durable publication marker, it atomically replaces
@@ -201,10 +239,13 @@ just peer-cli-charlie
 | Command                                             | Purpose                                                                  |
 | --------------------------------------------------- | ------------------------------------------------------------------------ |
 | `just setup`                                        | Install the Tauri CLI and frontend dependencies.                         |
-| `just run`                                          | Check the default fixture catalog and run the GUI.                       |
+| `just` / `just run`                                 | Run fixtures, or real data when `LANSPREAD_GAMES_DIR` is set.            |
-| `just build`                                        | Check the default fixture catalog and build without bundling.            |
+| `just run-fixture`                                  | Check the default fixture catalog and run the GUI.                       |
+| `just build`                                        | Validate production authority and build without bundling.                |
+| `just build-production PACKAGES_DIR`                | Generate/reuse production authority and build without bundling.          |
+| `just build-fixture`                                | Check the default fixture catalog and build without bundling.            |
 | `just bundle`                                       | Check production authority and build production bundles.                 |
-| `just catalog-generate-production PACKAGES_DIR`     | Hash and publish the complete production package corpus.                 |
+| `just catalog-generate-production PACKAGES_DIR`     | Hash, cache, and publish the complete production package corpus.         |
 | `just catalog-generate-production-game DIR GAME_ID` | Safely regenerate one game in an already complete catalog.               |
 | `just catalog-check-production`                     | Validate all production database/index/manifest artifacts.               |
 | `just fixture-catalog-check`                        | Validate the default development fixture catalog.                        |