ADFA-4954 fix(kolibri): review nits on the dashboard defects

authStatus had `e.status >= 500 ? 502 : 502` — both arms the same, so the
distinction it implied never existed. Settled as 502 for everything that is not
401/403, with the reason written down: echoing Kolibri's 4xx would blame the
app's caller for a request the app composed itself.

The installed check now answers present / absent / unknown, and only absent
refuses. A database that exists but cannot be read — SQLITE_BUSY while Kolibri
writes during an import — used to be reported as "not installed", telling the
user to import a channel they may already have. Unknown lets the request
through; Kolibri is the authority.

RemoteChannel is re-exported with `export type`, and imported with `import
type`: it is an interface with no runtime value, and a plain re-export stops
compiling under isolatedModules.

CHANGELOG: the English pass is REST-facing too — POST /credentials/kolibri
returns a different string on 401.

Verified: npm run typecheck clean, also clean with --isolatedModules, npm test
73/73.

Author: luisguzman-adfa

static/dashboard/CHANGELOG.md

@@ -4,7 +4,7 @@ One line per version, newest first. Every REST-facing change bumps the version i
 (the app surfaces it via `/system/dashboard/update-check` and the "Update available" pill), so this
 file is the human record of what each bump enables. Keep entries short: `version - change (TICKET)`.
 
-- **1.2.1** - Four Kolibri defects found by testing against a real device. `/kolibri/estimate` now reports free space (the call was missing the mandatory `?path=Content` and had been failing silently since it was written) and answers **409** with a readable message for a channel that is not installed, instead of letting Kolibri return a bare 500; `/kolibri/catalog` reports real sizes and resource counts (it was reading Studio's field names on an endpoint that uses Kolibri's); a failed import now carries the cause instead of just the exception class name. Also finishes the English pass: `routes.ts` was the last file the 1.1.6 sweep missed. (ADFA-4954)
+- **1.2.1** - Four Kolibri defects found by testing against a real device. `/kolibri/estimate` now reports free space (the call was missing the mandatory `?path=Content` and had been failing silently since it was written) and answers **409** with a readable message for a channel that is not installed, instead of letting Kolibri return a bare 500; `/kolibri/catalog` reports real sizes and resource counts (it was reading Studio's field names on an endpoint that uses Kolibri's); a failed import now carries the cause instead of just the exception class name. Also finishes the English pass: `routes.ts` was the last file the 1.1.6 sweep missed — REST-facing too, since one response string changes (`POST /credentials/kolibri` on 401). (ADFA-4954)
 - **1.2.0** - Self-update cutover baseline: no endpoint change, but from this version the app updates the dash-node core **live over REST** (`POST /system/dashboard/rebuild`, the blue-green rebuild from ADFA-5011) instead of a proot rebuild. Installs on < 1.2.0 still use the proot path to reach 1.2.0; 1.2.0+ update to 1.2.1+ via REST. (ADFA-5051)
 - **1.1.6** - Kolibri modules now in English. REST-facing because the diagnostic text changed: the `blockers[]` strings from `GET /kolibri/ready` and the `error` text on Kolibri jobs. Shapes, status codes and field names are unchanged.
 - **1.1.5** - Credentials: `POST /credentials/calibre` now validates against live Calibre-Web (401 on reject, save-unverified when the service is down); `GET /credentials/:service` returns the default password only while still at the factory default, for full form prefill. (ADFA-5044)

static/dashboard/routes.ts

@@ -378,10 +378,15 @@ function authStatus(e: unknown): number {
             default: return 502;
         }
     }
-    // Kolibri answered, but with an error: pass its semantics through instead of a 500.
+    // Kolibri answered, but with an error. 502 in every case that is not an auth
+    // one: whatever Kolibri's status was, from here it is an upstream we could not
+    // get a usable answer from, and echoing its 4xx would blame the app's caller
+    // for a request the app itself composed. (This used to read
+    // `e.status >= 500 ? 502 : 502` — both arms the same, so the distinction it
+    // implied never existed.)
     if (e instanceof KolibriApiError) {
         if (e.status === 401 || e.status === 403) return e.status;
-        return e.status >= 500 ? 502 : 502;   // upstream in a bad state
+        return 502;
     }
     // The request was well formed but a precondition is not met — the channel is
     // not on the device. That is the caller's state, not a server fault, so it

static/dashboard/sockets/kolibri.query.ts

@@ -24,8 +24,9 @@ import {
     KolibriSession, STUDIO_URL,
 } from './kolibri.session';
 import {
-    TASK_DELETE_CHANNEL, TERMINAL_STATES, mapPercent, toRemoteChannel, RemoteChannel,
+    TASK_DELETE_CHANNEL, TERMINAL_STATES, mapPercent, toRemoteChannel,
 } from './kolibri.map';
+import type { RemoteChannel } from './kolibri.map';
 
 const KOLIBRI_HOME = process.env.KOLIBRI_HOME || '/library/kolibri';
 const MAIN_DB = path.join(KOLIBRI_HOME, 'db.sqlite3');
@@ -120,8 +121,11 @@ export function contentBytesOnDisk(): number {
 
 // RemoteChannel and toRemoteChannel now live in kolibri.map.ts: the mapper is
 // pure, and the two competing sets of field names it reconciles deserve a unit
-// test rather than a comment. Re-exported so the routes keep their import path.
-export { RemoteChannel };
+// test rather than a comment. Re-exported so the routes keep their import path —
+// as `export type`, because RemoteChannel is an interface with no runtime value
+// and a plain re-export stops compiling the day isolatedModules or
+// verbatimModuleSyntax is switched on.
+export type { RemoteChannel };
 
 /**
  * Remote catalogue for the wizard's picker, through the device's own proxy.
@@ -267,7 +271,9 @@ export class ChannelNotInstalledError extends Error {
 export async function estimateSelection(
     channelId: string, nodeIds?: string[], excludeNodeIds?: string[],
 ): Promise<SelectionSize> {
-    if (!isChannelInstalled(channelId)) {
+    // ABSENT is a fact about the request; UNKNOWN is a fact about us. Only the
+    // first one is the caller's problem, so only the first one refuses.
+    if (installedState(channelId) === 'absent') {
         throw new ChannelNotInstalledError(
             `channel ${channelId} is not on the device: its remaining size can only be `
             + 'measured once its metadata has been imported');
@@ -310,22 +316,28 @@ export async function estimateSelection(
  * A single-row lookup, not the full inventory query: this runs before every
  * estimate and only needs a yes or no.
  */
-function isChannelInstalled(channelId: string): boolean {
-    if (!fs.existsSync(MAIN_DB)) return false;
+function installedState(channelId: string): 'present' | 'absent' | 'unknown' {
+    // No database at all means nothing has ever been imported, which is a real
+    // answer rather than a failure to look.
+    if (!fs.existsSync(MAIN_DB)) return 'absent';
     try {
         const db = new Database(MAIN_DB, { readonly: true });
         try {
             const row = db.prepare(
                 'SELECT 1 FROM content_channelmetadata WHERE id = ? LIMIT 1',
             ).get(channelId);
-            return row !== undefined;
+            return row === undefined ? 'absent' : 'present';
         } finally {
             db.close();
         }
     } catch {
-        // Unreadable database: treat as not installed, which produces the same
-        // actionable message rather than an opaque 500 from Kolibri.
-        return false;
+        // The database exists but could not be read — SQLITE_BUSY while Kolibri
+        // writes during an import is the realistic case. Reporting "not installed"
+        // here would tell the user to import a channel they may already have. Say
+        // we do not know, and let the request through: Kolibri is the authority,
+        // and if the channel really is missing it answers its own 500, which is
+        // where we started but only in the case we cannot rule out.
+        return 'unknown';
     }
 }