- useAsyncCallback: re-throw in catch to preserve rejection semantics;
  add no-op .catch wrapper in useAsyncCallback to suppress unhandled
  rejection warnings for fire-and-forget callers
- useAsyncCallback.test: expect rejects.toBe(boom) to assert rejection
- loginUtil: use != null guards for refresh_token / expires_in_ms to
  correctly handle zero/falsy-but-present values
- initMatrix: use typeof === 'number' guard for expires_in_ms expiry calc
- ClientRoot: pass activeSession.userId to both pushSessionToSW calls
  so the SW session record keeps a complete userId

- useAsyncCallback: re-throw in catch to preserve rejection semantics;
  add no-op .catch wrapper in useAsyncCallback to suppress unhandled
  rejection warnings for fire-and-forget callers
- useAsyncCallback.test: expect rejects.toBe(boom) to assert rejection
- loginUtil: use != null guards for refresh_token / expires_in_ms to
  correctly handle zero/falsy-but-present values
- initMatrix: use typeof === 'number' guard for expires_in_ms expiry calc
- ClientRoot: pass activeSession.userId to both pushSessionToSW calls
  so the SW session record keeps a complete userId

- useAsyncCallback: re-throw in catch to preserve rejection semantics;
  add no-op .catch wrapper in useAsyncCallback to suppress unhandled
  rejection warnings for fire-and-forget callers
- useAsyncCallback.test: expect rejects.toBe(boom) to assert rejection
- loginUtil: use != null guards for refresh_token / expires_in_ms to
  correctly handle zero/falsy-but-present values
- initMatrix: use typeof === 'number' guard for expires_in_ms expiry calc
- ClientRoot: pass activeSession.userId to both pushSessionToSW calls
  so the SW session record keeps a complete userId

- useAsyncCallback: re-throw in catch to preserve rejection semantics;
  add no-op .catch wrapper in useAsyncCallback to suppress unhandled
  rejection warnings for fire-and-forget callers
- useAsyncCallback.test: expect rejects.toBe(boom) to assert rejection
- loginUtil: use != null guards for refresh_token / expires_in_ms to
  correctly handle zero/falsy-but-present values
- initMatrix: use typeof === 'number' guard for expires_in_ms expiry calc
- ClientRoot: pass activeSession.userId to both pushSessionToSW calls
  so the SW session record keeps a complete userId

…e) (#611)

> Related to closed PR #548 (`fix/media-error-handling`), which was
split into smaller focused PRs.

### Description

`injectionPoint: undefined` was set in `vite.config.ts` to silence a
Workbox `AssertionError` about multiple `self.__WB_MANIFEST` occurrences
(an `if` guard in `sw.ts` plus the `precacheAndRoute()` call = two
matches; Workbox requires exactly one). The unintended consequence:
Workbox never injected the precache manifest, so **no assets were
precached** — every cold start hit the network instead of serving from
cache, and offline use was broken entirely.

Fix: remove the `if` guard in `sw.ts` (leaving exactly one
`self.__WB_MANIFEST` reference) then remove `injectionPoint: undefined`
from `vite.config.ts` to restore normal precaching behaviour.

Fixes #

#### Type of change

- [x] Bug fix (non-breaking change which fixes an issue)
- [ ] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality to not work as expected)
- [ ] This change requires a documentation update

### Checklist:

- [x] My code follows the style guidelines of this project
- [x] I have performed a self-review of my own code
- [x] I have commented my code, particularly in hard-to-understand areas
- [x] My changes generate no new warnings

### AI disclosure:

- [x] Partially AI assisted (clarify which code was AI assisted and
briefly explain what it does).
- [ ] Fully AI generated (explain what all the generated code does in
moderate detail).

The root cause diagnosis (two `self.__WB_MANIFEST` references causing
Workbox to silently skip injection) was identified with AI assistance. I
verified the fix by checking Workbox's `injectionPoint` behaviour and
confirming precaching was restored.

…er, and index.html (#609)

> Related to closed PR #548 (`fix/media-error-handling`), which was
split into smaller focused PRs.

### Description

Without explicit `Cache-Control` headers, browsers apply heuristic
caching to all responses — including `sw.js` and `index.html`. This
causes stale service workers and stale app shells to persist after a
deploy. Three header rules added to the Caddyfile:

- `/assets/*` — `public, max-age=31536000, immutable`: content-hashed
filenames change on every build, so these are safe to cache permanently.
- `/sw.js` — `no-cache`: must always be revalidated so the browser picks
up SW updates promptly.
- `/index.html` — `no-cache`: must always be revalidated so the browser
gets the latest asset hashes on load.

Fixes #

#### Type of change

- [x] Bug fix (non-breaking change which fixes an issue)
- [ ] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality to not work as expected)
- [ ] This change requires a documentation update

### Checklist:

- [x] My code follows the style guidelines of this project
- [x] I have performed a self-review of my own code
- [x] I have commented my code, particularly in hard-to-understand areas
- [x] My changes generate no new warnings

### AI disclosure:

- [x] Partially AI assisted (clarify which code was AI assisted and
briefly explain what it does).
- [ ] Fully AI generated (explain what all the generated code does in
moderate detail).

The cache header rules were partially AI assisted. I verified the
`immutable` directive is appropriate for content-hashed assets and that
`no-cache` (revalidate-always, not no-store) is correct for `sw.js` and
`index.html`.