Read Setup URI generator values from LIVESYNC_ variables

hostname, username, and the other unprefixed names collide with shell
and system variables (fish makes hostname read-only, Windows already
defines USERNAME). The generator now reads LIVESYNC_HOST, LIVESYNC_USER,
LIVESYNC_PASS, LIVESYNC_DB, and LIVESYNC_PASSPHRASE first and falls back
to the old names, so existing instructions keep working.

Co-authored-by: rwbru <59871009+rwbru@users.noreply.github.com>

utils/readme.md

@@ -31,21 +31,23 @@ Authentication and other non-retryable HTTP failures stop immediately. Network a
 
 The existing `flyio/generate_setupuri.ts` path remains a CouchDB-only compatibility wrapper for the Fly.io deployment script.
 
+The connection and Vault encryption values use a `LIVESYNC_` prefix so that they do not collide with shell or system variables such as `hostname` and `USERNAME`. The unprefixed names `hostname`, `username`, `password`, `database`, and `passphrase` are still read when the prefixed ones are not set.
+
 The generator creates a fresh random ID key by default and includes it in the encrypted Setup URI. It prints a tagged `sls-id-v1:` recovery code. Set `id_recovery_code` to that code when generating another URI for the same Vault; a new run without it creates a different key. This restores only the ID key: reuse the original connection details too. For P2P, provide the original `p2p_room_id` and `p2p_passphrase` because omitted values are generated afresh. Set `id_mode=legacy` to generate a URI with the previous ID behaviour. `id_mode=legacy` and `id_recovery_code` cannot be combined. Keep the recovery code private and retain it if every device might be lost.
 
 ### CouchDB
 
 ```sh
-export hostname=https://couch.example.com
-export username=couchdb-admin-username
-export password=couchdb-admin-password
-export database=obsidiannotes
-export passphrase=a-strong-vault-encryption-passphrase
+export LIVESYNC_HOST=https://couch.example.com
+export LIVESYNC_USER=couchdb-admin-username
+export LIVESYNC_PASS=couchdb-admin-password
+export LIVESYNC_DB=obsidiannotes
+export LIVESYNC_PASSPHRASE=a-strong-vault-encryption-passphrase
 export uri_passphrase=a-separate-setup-uri-passphrase # Optional
 deno run --minimum-dependency-age=0 --config=./flyio/deno.jsonc --frozen --lock=./flyio/deno.lock --allow-env ./setup/generate_setup_uri.ts
 ```
 
-If `uri_passphrase` is omitted, the tool generates and prints a cryptographically random one. Store the Setup URI and its passphrase separately. The `passphrase` value protects synchronised Vault data and must also be stored safely.
+If `uri_passphrase` is omitted, the tool generates and prints a cryptographically random one. Store the Setup URI and its passphrase separately. The `LIVESYNC_PASSPHRASE` value protects synchronised Vault data and must also be stored safely.
 
 The generator defaults to `uri_mode=ephemeral`. The URI opens only during the current fixed seven-day UTC window, and the tool prints its exact end time. It may have less than seven days remaining when generated. For an indefinitely reusable URI, set `uri_mode=persistent` before running the command. Persistent uses the existing encrypted format, which older clients that already support that format can read. The time condition controls opening the URI; it does not revoke settings or credentials after import.
 
@@ -59,7 +61,7 @@ export secret_key=<SECRET KEY>
 export bucket=vault-data
 export region=auto
 export bucket_prefix=team-a # Optional
-export passphrase=<A STRONG VAULT ENCRYPTION PASSPHRASE>
+export LIVESYNC_PASSPHRASE=<A STRONG VAULT ENCRYPTION PASSPHRASE>
 deno run --minimum-dependency-age=0 --config=./flyio/deno.jsonc --frozen --lock=./flyio/deno.lock --allow-env ./setup/generate_setup_uri.ts
 ```
 
@@ -69,7 +71,7 @@ Optional Object Storage variables are `use_custom_request_handler`, `force_path_
 
 ```sh
 export remote_type=p2p
-export passphrase=<A STRONG VAULT ENCRYPTION PASSPHRASE>
+export LIVESYNC_PASSPHRASE=<A STRONG VAULT ENCRYPTION PASSPHRASE>
 deno run --minimum-dependency-age=0 --config=./flyio/deno.jsonc --frozen --lock=./flyio/deno.lock --allow-env ./setup/generate_setup_uri.ts
 ```