rename: the docs say Inkwell, and nothing else still says ThoughtSync by accident

Step 6 of milestone 481. README, docs/*, ci-requirements.md, the desktop and
Arch READMEs, alembic.ini, .gitignore, the frontend package name, the service
worker's cache name (its activate handler deletes any cache by another name, so
the old one is cleaned up), and the Android names in the release body.

What still says thoughtsync does so on purpose (Scribe note 5071):
- the desktop data crossover (crossover.rs) and its startup log
- the old-export import marker
- the "Upgrading from ThoughtSync" block in .env.example, and compose's pointer
  to it
- the packages being retired: deb conflicts/replaces thought-sync, pacman
  thoughtsync and thoughtsync-desktop
- the Android signing keyAlias, which names a key in the existing keystore
- history: shipped alembic migrations, and the test-binary hashes that
  ci-requirements.md records from 2026-08-18

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/android-distribution.md

@@ -1,6 +1,6 @@
 # Getting the Android app onto your server
 
-ThoughtSync's server hands out the Android client it syncs with. Once an APK is in
+Inkwell's server hands out the Android client it syncs with. Once an APK is in
 place, anyone with an account on that server can download it from **Account →
 Linked devices**, and linked phones can update themselves from it.
 
@@ -34,7 +34,7 @@ pinning.
 ## Overriding it
 
 If you want a specific build — testing something, or holding back — drop it in
-`/var/thoughtsync/client/` and it wins over the image's copy.
+`/var/inkwell/client/` and it wins over the image's copy.
 
 That directory is shared with the desktop clients the server hands out, and
 **precedence is decided per platform**: dropping in an APK overrides the baked APK
@@ -44,14 +44,14 @@ Two files, both required:
 
 | File | What it is |
 | --- | --- |
-| `thoughtsync.apk` | the client |
-| `thoughtsync-android.json` | `{version_name, version_code, size, sha256}` |
+| `inkwell.apk` | the client |
+| `inkwell-android.json` | `{version_name, version_code, size, sha256}` |
 
 The sidecar exists because an APK keeps its version in a binary manifest that
 needs the Android build tools to read. CI writes it beside the APK, where the
 real values are already known.
 
-`/var/thoughtsync` is the same volume that holds attachments (`Config.DATA_DIR`),
+`/var/inkwell` is the same volume that holds attachments (`Config.DATA_DIR`),
 so a build dropped there survives container recreation — and survives an image
 upgrade, which is the point of an override.
 
@@ -59,10 +59,10 @@ Both files are published to the rolling dev-channel release (tag `dev-rolling`)
 on every green Android build:
 
 ```sh
-REPO=https://git.fabledsword.com/bvandeusen/thoughtsync
+REPO=https://git.fabledsword.com/bvandeusen/inkwell
 TOKEN=...   # a Fabled-Git token with read access; the instance is private
 
-for f in thoughtsync.apk thoughtsync-android.json; do
+for f in inkwell.apk inkwell-android.json; do
   curl -fsSL -H "Authorization: token $TOKEN" \
     -o "/tmp/$f" "$REPO/releases/download/dev-rolling/$f"
 done
@@ -70,8 +70,8 @@ done
 # Copy the sidecar LAST. A sidecar that does not match the APK beside it is not a
 # client, so a half-finished copy falls back to the image's build rather than
 # advertising a lie.
-docker compose cp /tmp/thoughtsync.apk app:/var/thoughtsync/client/
-docker compose cp /tmp/thoughtsync-android.json app:/var/thoughtsync/client/
+docker compose cp /tmp/inkwell.apk app:/var/inkwell/client/
+docker compose cp /tmp/inkwell-android.json app:/var/inkwell/client/
 ```
 
 To go back to whatever the image ships, delete both files.
@@ -88,7 +88,7 @@ offering a button that fails.
 
 ## What happens if you get it wrong
 
-All of these describe an override in `/var/thoughtsync/client/`. A broken
+All of these describe an override in `/var/inkwell/client/`. A broken
 override does not take the feature away — it falls through to the build the image
 shipped with, which is the whole reason precedence runs in that direction.